JP2012100547A - Method and apparatus for producing organic matter by feeding gas resource to anaerobic microorganism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed a gas resource and to retain an anaerobic ambience in a method for producing an organic matter by an anaerobic microorganism from gas resources such as CO, carbon monoxide (CO) and hydrogen (H) as raw materials.SOLUTION: By paying attention to a gas-permeable membrane, feeding of gas resources to the anaerobic microorganism and retention of the culture environment for the anaerobic microorganism are achieved. Specifically, by the gas exchange between a liquid phase and a gas phase via a gas exchange membrane such as a hydrophobic gas-permeable membrane, the gas resources are fed to the anaerobic microorganism, and deoxidization from the microorganism growing environment is possible. Further, the anaerobic ambience can be easily retained by introducing a deoxidization step into a gas circulation pathway, and the amount of feeding of gas substrate can be adjusted by adjusting the gas composition of the gas phase.

Description

  The present invention relates to a method and an apparatus for producing an organic substance by supplying a gaseous resource to an anaerobic microorganism. More specifically, the present invention relates to a method and an apparatus for producing an organic substance by supplying a gaseous resource to a fermentation broth while maintaining an anaerobic atmosphere in an organic substance production process from the gaseous resource by an anaerobic microorganism.

  Ethanol fermentation and acetic acid fermentation using anaerobic microorganisms have been performed for a long time. Generally, agricultural products such as sugars and grains are used as raw materials used in the classical fermentation reaction. Methods for producing alcohols and organic acids, which are organic substances, from these raw materials have been known for a long time. Specifically, a method for producing ethanol, butanol, acetic acid, lactic acid or the like using a microorganism is known. Furthermore, in recent years, microbial fermentation has attracted attention as a method for producing ethanol for fuels from plant-derived resources by ethanol fermentation. Ethanol production by microbial fermentation has been performed for a long time, but ethanol produced as an alternative energy for petroleum is particularly called “bioethanol” or the like. Similarly, techniques for converting plant-derived renewable resources into useful organic substances such as organic acids, alcohols, aldehydes, esters and the like by appropriately selecting microorganisms and fermentation conditions have been studied.

In the method of converting plant-derived resources into useful organic substances by fermentation, most of the raw materials used by microorganisms as resources are glucose. In practice, starch is derived from cereal grains, sugar or molasses itself as raw materials, and glucose is produced by the action of enzymes and microorganisms themselves. These raw materials are inherently valuable hydrocarbon sources for food and feed. In other words, the classic fermentation reaction consumes a valuable hydrocarbon source as a raw material. Therefore, there were many problems from the viewpoint of effective use of the resources themselves and the economic viewpoint. It is fresh in memory that the rapid spread of bioethanol has led to a surge in global grain prices. In order to avoid competition with food, attempts have been made to use non-edible plant resources. Specifically, the use of cellulose resources such as wood and firewood has been proposed.
However, microorganisms that produce organic matter cannot directly use these plant resources. Therefore, it is necessary to decompose plant resources into sugars such as glucose in advance before fermentation with microorganisms. Specifically, an auxiliary process such as pre-conversion of cellulose resources into carbohydrates that can be easily used by cells by enzyme treatment or physical decomposition is required.

  In contrast to the classic fermentation reaction that assimilate sugars such as glucose, a method for producing an organic substance that is a valuable resource using gas as a resource can be expected to have the following advantages. That is, first, an organic substance can be produced from a raw material that does not compete with food. For example, carbon-containing gases such as carbon dioxide and carbon monoxide have been regarded as inorganic substances that are usually difficult to use. Therefore, it was normally released as it is into the atmosphere. Or, after the combustion treatment (oxidation treatment), it was also released into the atmosphere. Therefore, the technology to convert a mixed gas (syngas) containing carbon dioxide, carbon monoxide, hydrogen, etc. into valuable materials with fixed carbon, such as organic substances such as organic acids, alcohols, aldehydes, esters, etc. is very attractive. Is. In particular, carbon dioxide, which is required to reduce the release to the atmosphere as a greenhouse gas, has an important significance in recent years in that it is converted into an organic substance that is useful as a resource without being released to the atmosphere as much as possible.

Currently, many of valuable organic acids, alcohols, aldehydes, esters and the like are separated or chemically synthesized directly from hydrocarbon sources originating from fossil fuels such as natural gas, petroleum and coal. Even if these hydrocarbon sources are once used as a gas resource through a synthesis gasification process using a gasifier, etc., the target is obtained by subjecting the gas resource to a chemical reaction at a high temperature and pressure using a metal catalyst or the like. Organic matter is synthesized.
For example, a method of synthesizing acetic acid, which is very important as an organic acid, using oxidation of acetaldehyde, butane, naphtha, ethylene or the like is known. At present, acetic acid is mainly obtained by a methanol method in which carbon monoxide generated in a gasification furnace and methanol are subjected to a carbonylation reaction from an inexpensive hydrocarbon source. In the methanol method, methanol and carbon monoxide are mixed at high temperature and high pressure in the presence of a metal catalyst such as rhodium or iridium, which are also rare metals, and acetic acid is produced according to the following reaction formula.
CH ₃ OH + CO → CH ₃ COOH

  In these chemical acetic acid synthesizing methods, in many cases, carbon dioxide is produced mainly by gasification or heating. However, the carbon dioxide produced as a secondary is currently released into the atmosphere as it is. A large amount of carbon dioxide is also emitted in industrial processes in various manufacturing industries such as thermal power generation, cement production, and steel production. Again, carbon dioxide has been released into the atmosphere without being used as a gaseous resource.

It has been known more academically that organic substances such as acetic acid and ethanol are produced from the gas resources by the metabolism of anaerobic microorganisms. As an anaerobic microorganism, for example, the following microorganism has been found as a microorganism that produces acetic acid using a gas resource such as carbon monoxide or carbon dioxide as a carbon source.
Acetobacterium genus Clostridium genus Eubacterium genus Bacteroides genus Sporomusa genus Acetogenium genus Moorella

These microorganisms are classified as so-called absolute autotrophic bacteria. Therefore, these microorganisms are generally anaerobic, and when oxygen is present in the growth system, their growth tends to be inhibited. In addition, these microorganisms grow outside the cell through a production process that includes acetic acid in the metabolic pathway under conditions of almost normal temperature and normal pressure while growing with carbon monoxide and carbon dioxide as the carbon source and hydrogen gas as the energy source. Release organic matter. For example, it is known that microorganisms produce 1 mole of acetic acid from 2 moles of carbon dioxide and 4 moles of hydrogen according to the following reaction (Japanese Patent Laid-Open No. 01-098472, J. Biosci. Bioeng., 2005, 99, 252). -258, Next Generation Industrial Technology Research and Development System, Bioreactor Research and Development General Report, 1981-63, etc.
2CO ₂ + 4H ₂ → CH ₃ COOH

In addition, there are the following reports on the use of microorganisms that assimilate gases.
* A novel genus Clostridium or a derivative genus that produces ethanol and acetic acid from carbon dioxide and hydrogen (Japanese Patent Laid-Open No. 2003-339371)
* Anaerobic microorganisms that produce ethanol and acetic acid from carbon oxides and hydrogen (Special Table No. 2004-504058)
* Method of recovering waste gas discharged from various chemical industry processes as valuable organic matter by microbial fermentation (Special Table 2000-513233)
Furthermore, a technique for improving the amount of ethanol produced by anaerobic microorganisms that assimilate synthesis gas mainly composed of carbon monoxide, carbon dioxide, and hydrogen has been reported. That is, among the metabolic pathways of these gases, this is a method in which ethanol is preferentially produced by bacterial cells by intentionally inhibiting the pathway for producing acetic acid from acetyl-CoA contained in the acetic acid production metabolic pathway (Toyama et al. Mitsui Engineering & Shipbuilding Technical Report, No. 197 (2009-6) p.23).
If the method for converting a gas resource into a useful organic material by microbial fermentation as described above can be applied to an industrial production technique, the organic material can be obtained from the gas resource by a method with less environmental load. Moreover, if carbon dioxide, which has been discarded in the past, is combined as a gas resource that is a raw material, it leads to recycling of carbon dioxide.

  In fermentation using gas resources, a method of supplying gas resources to microorganisms becomes a problem. A diffused absorption method is generally used as a means for supplying gas to the fermentation broth. FIG. 2 shows a typical structure of a fermenter for performing the diffuse absorption method. In the fermenter of FIG. 2, the gaseous resource is directly introduced into the fermenter and stirred. The diffuse absorption method supplies gas resources as fine bubbles from the air diffuser at the bottom of the fermentation broth, and stirs the fermenter at high speed, so that the air bubbles floating in the fermentation broth stay in the fermentation broth as long as possible. It is a method of making it take in. In the diffuse absorption method, there is a problem that most of the supplied gas floats as a gas from the fermentation broth. Under such conditions, the supplied gas simply passes through the culture solution and is not dissolved and stored in the fermentation solution, so it is released from the fermentation solution without being used by microorganisms. Will be. In order to increase the utilization rate of the gas, there has been no choice but to perform a gas circulation method in which most of the gas that has emerged from the fermentation broth is collected and repeatedly supplied to the fermentation broth.

  In order to improve the absorption efficiency to the fermentation broth or microorganisms while the bubbles are floating in the fermentation broth, measures such as reducing the size of the bubbles and increasing the number of bubbles are devised by devising a device and conditions for aeration. Has been taken. However, the blast energy of the gas circulated wastefully without being absorbed by the fermented liquid becomes a very large burden. Alternatively, for the purpose of improving the dissolution efficiency of gas resources in a liquid, it is also known to use a special air diffuser that makes bubbles as small as possible in order to increase the gas-liquid contact area in the fermentation broth. However, in order to supply gas resources through the fine holes, a strong supply pressure is required, and there is a problem that the air pressure loss increases. In addition, even in a technique such as stirring the entire fermentation broth at a very high speed in order to suppress the bubble floating speed, there is a problem that a great amount of energy is consumed simply by stirring the liquid. For these reasons, the fermentation method in which gas resources are assimilated using microorganisms has a problem of increasing energy loss. Furthermore, in the aeration absorption method, the fermented liquid components and microbial cells aggregated and floated on the air bubble interface (floating), or the microbial cells were damaged by the shearing force by vigorous stirring.

  As a special aeration method, methods using microbubbles in the fermentation broth have also been proposed (for example, JP 2007-312689, JP 2007-82438). Actually, microbubbles having a diameter (bubble diameter) of about several tens of μm (microbubbles) or several hundred nm or less (nanohables) are used. However, in these known techniques, the miniaturization of bubbles is aimed at simply stimulating and activating microorganisms or making the management and processing of the fermentation broth easier. In order to generate microbubbles through the micropores, energy for increasing the air pressure is required, but microbubbles are selected for this purpose. Moreover, in order to supply all the amount necessary for the metabolism of the microbial cells with microbubbles such as microbubbles and nanohables, it is unrealistic that a large number of microbubbles must be supplied to the fermenter. This is because the volume of bubbles is originally very small and the amount of gas supplied per bubble is significantly limited. Therefore, there is a limit to supplying gas resources to the cells by gas miniaturization.

  There has also been proposed a fermentation method in which a gas having low solubility in water, such as hydrogen or carbon monoxide, is supplied to cells through a porous membrane (Japanese Patent Laid-Open No. 2007-83437). However, this method is only a proposal for unilaterally supplying a gas having low solubility in water from the porous membrane to the fermentation broth. In reality, microorganisms that assimilate gas assimilate gas at a certain rate regardless of gas solubility. If there is a significant difference in solubility between the gases to be utilized, the less soluble gas resource will be depleted. However, simply improving the supply of gas resources with low solubility, when used as a gas resource with a gas such as carbon dioxide with high solubility in water, cannot maintain a gas supply that matches the gas consumption balance of the bacterial cells.

  In particular, the fermentation broth is an aqueous solution, whereas gaseous resources such as hydrogen and carbon monoxide have low solubility in water. For example, in the case of a typical absolute anaerobic bacterium that produces an organic substance from a gaseous resource, the molar ratio of carbon dioxide and hydrogen required for microbial metabolism is 1: 1 or more, usually 1: 2 to 3 or more. In other words, the incorporation of very low hydrogen into the fermentation broth was the rate-limiting factor in organic matter production compared to carbon dioxide, which has a very high solubility in water.

In addition, the solubility of oxygen that destroys the anaerobic atmosphere in water is higher than that of gas resources with low solubility such as hydrogen and carbon monoxide. For this reason, the usual physical degassing means cannot easily perform the deoxygenation treatment while supplying a gaseous resource to the fermentation broth. Therefore, there has been a problem that a large amount of an expensive reducing agent such as cysteine must be contained in order to maintain the anaerobic atmosphere of the fermentation broth.
In order to supply a sufficient amount of gas resources to the fermentation broth, the following measures can be considered.
* Increase the amount of dissolution by increasing the gas supply pressure very much * Reduce the temperature of the liquid and increase the amount of gas resources dissolved in water, that is, the fermentation broth. There was a risk of hindering fermentation. Keeping the temperature of the fermentation broth low also helps to dissolve oxygen.

Therefore, in addition to the problem of supplying gas resources to the cells, it is important to maintain the anaerobic atmosphere of the fermentation broth when the microorganisms involved in fermentation are anaerobic bacteria. For anaerobic bacteria such as Acetobacteria, it is necessary to manage the culture environment fairly strictly. Until now, the following measures have been taken especially in the fermentation of absolute anaerobic bacteria.
* Isolate and seal the fermentor and incidental equipment from the atmosphere to prevent oxygen contamination * Strictly deoxygenate the gas resources to be supplied * Add oxygen absorber to the fermentation broth to maintain a constant concentration Oxygen absorber Is added in preparation for addition of oxygen to the fermenter to maintain fermentation, for example, oxygen contamination from supplemental media, feed water, pH adjuster, etc., or generation of oxygen from the fermentation broth itself. Needless to say, it is necessary to select a mild reducing agent that does not become a microbial toxin as an oxygen scavenger for maintaining an anaerobic atmosphere in addition to the fermentation broth. Therefore, for example, expensive cysteine has been used as the oxygen scavenger.

Many microorganisms that metabolize carbon monoxide, carbon dioxide and hydrogen to produce acetic acid and ethanol are anaerobic bacteria as described above, and their growth is inhibited when oxygen is present in the growth system. Therefore, it is not desirable to use carbon dioxide exhaust gas containing considerable oxygen such as combustion gas as a gas resource as it is. For example, Japanese Patent No. 4101295 describes a method of producing acetic acid by the action of microorganisms using waste gas from a factory or the like containing hydrogen and carbon monoxide as a raw material. However, the actual factory exhaust gas contains more or less non-negligible amounts of oxygen, so it would be undesirable to use it as a gaseous resource for microorganisms.
Thus, it is practical to industrially maintain the fermentation solution in an anaerobic atmosphere while supplying gas resources containing carbon monoxide, carbon dioxide and hydrogen to the culture solution of anaerobic bacteria. It was difficult.

Japanese Unexamined Patent Publication No. 01-098472 JP 2003-339371 A Special table 2004-504058 Special table 2000-513233 JP 2007-082438 A JP2007-082437 Special table 2007-312689 Japanese Patent No.41012295

J. Biosci. Bioeng., 2005, 99, 252-258 Next Generation Industrial Technology Research and Development System, Bioreactor Research and Development Summary Report, 1986-63 (p195-229) Toyama et al., Mitsui Engineering & Shipbuilding Technical Report, No. 197 (2009-6) p. 23 Marcel Mulder, supervised by Yoshikawa et al., "Membrane Technology 2nd Edition", p320-325, IPC (1997)) Otsuki Hiroshi, Practical Industry Information, 29, 417, 2002.

  An object of the present invention is to provide a method or an apparatus for producing an organic substance by supplying gas resources such as carbon monoxide, carbon dioxide and hydrogen to an anaerobic microorganism. Or this invention relates to the method of supplying a gaseous resource to the fermented liquor containing an anaerobic microorganism. In yet another aspect, the present invention provides a method for maintaining a culture environment for anaerobic microorganisms, or an apparatus therefor.

  According to the present invention, there has been provided a technique capable of industrially and efficiently producing organic substances such as acetic acid and ethanol using carbon monoxide, carbon dioxide and hydrogen as gas resources and utilizing the metabolism of anaerobic microorganisms. In particular, carbon monoxide, carbon dioxide, and hydrogen, which are gas resources, can be obtained not only from fossil fuels but also from plant resources and organic wastes that do not become food by passing through a gasification step. If organic materials can be produced industrially using gas resources, these organic materials can be used for the production of organic materials, and the raw materials can be diversified. As a result, an organic material that does not compete with food can be used as a raw material, and a production method of a valuable material with a small environmental load can be put into practical use.

In the present invention, gas resources can be efficiently supplied to anaerobic microorganisms by operating under specific conditions using a hydrophobic gas permeable membrane. Furthermore, in a preferred embodiment of the present invention, an anaerobic atmosphere, which is a growth condition for bacterial cells, can be given to the fermentation broth and maintained. In the culture of known anaerobic bacteria, it is necessary to add an expensive oxygen scavenger to the culture solution in order to maintain an anaerobic atmosphere. However, in the present invention, the oxygen exchange can be performed easily and continuously by the gas exchange membrane. That is, the present invention provides, in a preferred embodiment thereof, a production method and a simpler production apparatus that can realize high productivity, low cost and stable drivability in anaerobic fermentation utilizing gas. In particular, when the fermentation broth is an aqueous solution, it becomes possible to supply a gas resource having low solubility in water with less energy. Moreover, in this invention, it is not necessary to give the fermented liquor the strong shear pressure which has a possibility of damaging a microbial cell.
In the present invention, as the carbon dioxide supplied to the anaerobic microorganisms, it is possible to reduce the carbon dioxide discharged into the atmosphere by using oxygen dioxide that has been discharged into the atmosphere.

  The organic substance production method using anaerobic microorganisms realizes production of an organic substance as a valuable substance at about normal temperature and normal pressure using carbon dioxide released into the atmosphere as a carbon source. In addition, since microbial fermentation does not require high temperature or high pressure for the intracellular reaction, it is possible to realize a method for synthesizing organic substances with excellent energy efficiency. Furthermore, since a catalyst such as a rare metal necessary for chemical synthesis is not required, it can be said that the raw material used is a method having a low environmental load.

  Further, in the present invention, the gas resource is supplied to the aqueous medium (fermented liquid) through the gas permeable membrane. Since microorganisms cannot pass through the gas permeable membrane, it is not necessary to sterilize the gas resources in advance. In the present invention, various additional steps such as gas circulation and replenishment, deoxygenation, and addition of water vapor can be combined on the gas phase side. Even when these series of additional treatments are performed, the gas phase is always separated from the aqueous medium (fermentation liquid) and the gas permeable membrane, and the liquid phase side is maintained aseptically. In addition, components such as an oxygen scavenger used in an additional step on the gas phase side are not brought into the aqueous medium, so that a wide range of components can be used.

It is a figure which shows the basic composition of the apparatus for manufacture of the organic substance based on this invention. It is a figure which shows the structure of the typical well-known apparatus for manufacturing organic substance using utilization of the gas resource by an anaerobic microorganism. It is a process flow figure showing an example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. In the gas supply device (104), an interface between the fermentation broth (102) and the gas phase part (104b) is formed through the hydrophobic gas permeable membrane (104a), and gas exchange is performed. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. An oxygen absorbing means is added in the gas circulation circuit of the gas supply apparatus shown in FIG. The gas constituting the gas phase part (104b) comes into contact with the oxygen scavenger (112; preferably liquid) disposed in the gas circulation circuit, and oxygen is absorbed. A broken line in the figure indicates a place where the gas resource (101) and the gas supply valve (110d) can be connected. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. The example which connected the fermenter (103) to the aspect shown in FIG. 4 is shown. A stirrer (113), various sensors (114), and the like can be added to the fermenter (103). In the figure, the broken line indicates a place where the fermented liquid-containing valve (110b) and the feed liquid (102d) can be connected. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. It is the example which provided the filtration apparatus (106) between the fermenter (103) and the gas supply apparatus (104) in the aspect of FIG. The filtrate (102b) from which the microbial cells have been removed is taken out from the fermentation broth (102) in the fermenter (103) by the filtration membrane (106a) in the filtration device (106), and is supplied to the gas supply device (104). Supplied. A broken line in the figure indicates a place where the return liquid adjusting valve (110l) can be connected. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. FIG. 6 shows an example in which an organic substance extraction device (107) is further added between the filtration device (106) and the gas supply device (104). The extraction device (107) is supplied with a solvent for organic matter extraction, and the organic matter accumulated in the fermentation broth is extracted. And the solvent which extracted organic substance is transferred to an organic substance separator (108), and organic substance is isolate | separated from a solvent. A broken line in the figure indicates a place where the return liquid adjusting valve (110l) can be connected. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. An example in which a hydrogen recovery device (111) is combined with the gas supply device (104) shown in FIG. The hydrogen recovery device (111) includes a hydrogen separation membrane (111a), selectively separates hydrogen in the gas phase, and returns to the gas phase section (104b) again as a gas resource (101c) from which hydrogen is recovered. A broken line in the figure indicates a place where the gas resource (101) and the gas supply valve (110d) can be connected. It is a process flow figure showing another example of composition of an organic matter production device using gas resources by an anaerobic microorganism of this embodiment. 1 shows a basic configuration of an organic matter production apparatus according to the present invention, including a fermenter (103), a filtration apparatus (106), and a gas supply apparatus (104). A broken line in the figure indicates a place where the return liquid adjusting valve (110l) can be connected.

Organic production equipment: 100
Gas resources: 101
Gas resource after gas supply device treatment: 101a
Waste gas resources: 101b
Gas resources from which hydrogen was recovered: 101c
Residual gaseous resources from which hydrogen was recovered: 101d
Fermented liquid: 102
Fermented liquid after gas supply device treatment: 102a
Filtrate: 102b
Concentrate: 102c
Supply liquid: 102d
Filtrate after extraction treatment: 102d
Fermenter: 103
Liquid phase part of fermenter: 103a
Gas phase part of fermenter: 103b
Gas supply device: 104
Hydrophobic gas permeable membrane: 104a
Gas phase part of gas supply device: 104b
Liquid phase part of gas supply device: 104c
Gas phase buffer tank: 105
Filtration device: 106
Filtration membrane: 106a
Extraction device: 107
Organic substance separation device: 108
Fermented liquid supply pump: 109a
Gas circulation pump: 109b
Filtrate supply pump: 109c
Extraction residue supply pump: 109d
Extract liquid pump: 109e
Fermentation liquid circulation valve: 110a
Fermented liquid valve: 110b
Fermentation liquid discharge valve: 110c
Gas supply valve: 110d
Waste gas valve: 110e
Fermentation liquid adjustment valve: 110f
Gas disposal valve: 110g
Fermentation liquid removal valve: 110h
Concentrate valve: 110i
Filtrate extraction valve: 110j
Organic matter production equipment: 200
Circulating gas adjustment valve: 110k
Return liquid adjustment valve: 110 l
Gas disposal valve for hydrogen recovered residue: 110m
Filtrate circulation valve: 110n
Hydrogen recovery unit: 111
Hydrogen separation membrane: 111a
Oxygen absorber: 112
Stirrer: 113
Various sensors: 114
Extract containing organic matter produced by microorganisms: 115
Organic matter produced by microorganisms: 116
Extract: 117
Organic matter production equipment: 300
Organic matter production equipment: 400
Organic matter production equipment: 500
Organic matter production equipment: 600

  The present inventors have paid attention to the supply of gas resources to a culture solution in order to efficiently obtain organic substances at low cost by anaerobic microorganisms that assimilate gas resources and give organic substances. Specifically, in a conventional method such as a diffused absorption method, supply of gas resources that are difficult to dissolve in water such as hydrogen and carbon monoxide is limited.

  On the other hand, as a means for absorbing gas into the liquid, or degassing processing for removing gas from the liquid, that is, means for performing mass transfer (gas absorption, desorption) between the liquid and the gas, it is called “membrane contactor”. There are also known methods. This is a method of moving or separating substances (gas molecules) between liquid-liquid and gas-liquid through a membrane. For example, a blood oxygen enrichment method called an artificial lung is known as a technique for performing gas absorption through a typical membrane. The “membrane contactor” is a method different from a general air diffusion absorption method or a gas absorption tower in which gas and liquid are brought into direct contact with each other through a membrane.

  For example, a non-porous membrane used for an artificial lung is a gas permeable membrane. The artificial lung can temporarily replace or assist lung function by contacting the blood taken from the human body with a gas through a non-porous membrane, allowing oxygen to be absorbed into the blood, and then returning it to the body again . The non-porous membrane is made of a gas permeable membrane having a high oxygen permeability such as silicone. In the artificial lung composed of a gas permeable membrane, oxygen is supplied through the gas permeable membrane instead of bubbling blood with gas (air or oxygen gas). In this case, unlike the bubbling method, there is an advantage that the liquid and gas are not in direct contact and it is difficult to damage blood components such as red blood cells. However, once the gas dissolves inside the membrane material, Since the inside of the non-porous membrane is diffused according to the pressure difference, there is a problem that a sufficient amount of gas cannot be permeated through the membrane even if the thickness is reduced within the range in which the mechanical strength of the membrane can be maintained.

  On the other hand, by utilizing the fact that an aqueous solution such as blood cannot penetrate into the microporous part due to the capillary pressure phenomenon, a gas-liquid interface between the gas phase and the liquid phase maintained by the porous film is directly formed on the hydrophobic microporous film. “Membrane contactors” are also known. In this type of “membrane contactor”, gas exchange of gas components is performed by the partial pressure difference between the components contained between the two. For example, in the case of artificial lung use, blood has a high oxygen solubility and also contains a component that selectively absorbs oxygen, such as hemoglobin. Therefore, blood easily absorbs oxygen from the gas phase (air or oxygen gas). On the other hand, blood before artificial lung treatment has a low oxygen concentration and a high carbon dioxide concentration. For example, even if air itself containing a little carbon dioxide and having a low oxygen concentration is used in the gas phase, Carbon easily disperses in the gas phase. As a result, it was possible to easily absorb oxygen into the blood and carbon dioxide into the gas through the membrane. In this case, since the gas-liquid interface is maintained by the micropores of the membrane, a large amount of microbubbles are not generated in the liquid phase compared to the diffuse absorption method or gas absorption tower, and the mixture of the gas and liquid phases There were advantages such as not occurring.

  In addition, the gas-liquid type “membrane contactor” selectively and easily incorporates useful components from the gas phase into the liquid phase by dissolving the absorbent that selectively incorporates gas components into the liquid phase. You can also For example, a method for separating gaseous ethane and ethylene by dissolving a special ethylene carrier compound in the liquid phase has been proposed (Marcel Mulder, supervised by Yoshikawa et al., "Membrane Technology 2nd Edition", p320- 325, IPC (1997)).

  On the other hand, the above-mentioned “membrane contactor” is also used for the degassing and gas dissolution treatment of liquids used in medicine, food, electronics industry, and the like. In the degassing, a gas having low solubility in water is flowed to the gas phase side as a sweep gas, or the gas dissolved in a liquid such as water is removed from the liquid by depressurizing the gas phase side. In water, the main purpose is to remove particularly highly soluble oxygen and carbon dioxide together with water vapor. Conversely, gas dissolution treatment is used as a method for producing carbonated water, for example, by supplying carbon dioxide with high water solubility to the gas phase and absorbing it in water on the liquid phase side (Hiroshi Ohtsuki, Practical Industry). Information, 29, 417, 2002.).

  Whether degassing or gas dissolution, a microporous membrane made of a hydrophobic polymer such as polyethylene or polypropylene is often used. Specifically, Liqui-Cel (registered trademark) manufactured by Celgard, SEPAREL (registered trademark) manufactured by DIC, and the like are known. However, in the case of SEPAREL (registered trademark) of DIC, since there is an extremely thin film on the surface of the hydrophobic microporous film, no direct gas-liquid interface is formed, and gas components dissolve and diffuse in the film. It is supposed to move between both phases.

However, in the known degassing and gas dissolution treatments, the gas to be treated is a gas having high solubility in the liquid phase. In addition, in the gas dissolution treatment, since the value of the gas supplied to the gas phase is extremely lower than the liquid, it includes a gas component that could not be absorbed into the liquid phase and an unnecessary component that was absorbed from the liquid to the gas side. The gas phase gas after the treatment has a low utility value and is usually discarded as it is and is not reused. In addition, when the sweep gas is used, the sweep gas is absorbed in the liquid phase by the difference in partial pressure, so that there is a problem that unnecessary components are dissolved in the liquid phase.
Furthermore, when the liquid is an aqueous solution, if the vapor phase does not contain water vapor, a considerable amount of water flows out into the gas phase as water vapor. When a volatile component other than gas is contained in the liquid, the volatile component flows out into the gas phase in the same manner as water vapor, but these must be discarded.

  As described above, even in a gas dissolution method through a gas permeable membrane, there is no known method for supplying gases having different solubility in an appropriate balance. Or since the simple method for maintaining an anaerobic atmosphere is not provided, the industrial use itself of the anaerobic microorganisms was restricted. The inventors of the present invention have found a condition in which a culture solution and a gas resource are brought into contact with each other through a gas exchange membrane, and the supply of the gas resource to the culture solution and the construction and maintenance of an anaerobic atmosphere can be easily realized. Was completed. That is, the present invention provides the following organic material production method and apparatus therefor.

[1] Anaerobic microorganisms that produce organic substances by assimilating either or both of (1) H ₂ and (2) CO ₂ and CO are anaerobically cultured in an aqueous medium and accumulated in the aqueous medium A method for producing an organic substance that recovers an organic substance assimilated by a microorganism from the aqueous medium, comprising the following steps:
(a) contacting the aqueous medium with a gas phase containing at least one gas of H ₂ , CO ₂ , and CO through a gas permeable membrane that allows permeation of the gas; Forming an interface for gas exchange with
at the interface of the (b) (a), and H _2, CO _2, and CO and 0 ₂ of the respective partial pressures respectively a1, a2, a3 and a4 in the gas phase, the pressure possessed by the gas contained in the aqueous medium Is b1, b2, b3 and b4, the partial pressure on the gas phase side is maintained at a1> b1, a2> b2, a3> b3, and a4 <b4, and the gas phase is separated from the interface of (a). Absorbing the gas in the aqueous medium and dispersing oxygen in the aqueous medium in the gas phase; and
(c) A step of recovering the assimilated organic matter accumulated in the aqueous medium from the aqueous medium.
[2] The method according to [1], wherein the gas permeable membrane is a gas permeable membrane made of a hydrophobic material.
[3] The hydrophobic material is any material selected from the group consisting of polyethylene / PE, polypropylene / PP, polytetrafluoroethylene / PTFE, poly-4 methylpentene 1, and silicone rubber, or a composite material thereof. The method according to [2].
[4] The hydrophobic material is made of any material selected from the group consisting of polyethylene / PE, polypropylene / PP, and polytetrafluoroethylene / PTFE, or a composite material thereof. The method according to [3], wherein the gas permeable membrane made of the composite material is a microporous membrane.
[5] The method according to any one of [1] to [4], wherein the gas phase is composed of a gas from which O ₂ has been removed.
[6] The method according to any one of [1] to [5], further including a step of maintaining the O ₂ partial pressure of the gas constituting the gas phase at 3 kPa or less.
[7] The gas constituting the gas phase contains (1) H ₂ and (2) either CO ₂ or CO, or both, and the proportion (molar ratio) of (1) H _{2 in} the gas is (2) The method according to any one of [1] to [4], which is equal to or greater than the sum of CO ₂ and CO.
[8] The method according to any one of [1] to [4], further including a step of circulating a gas constituting the gas phase in the gas circuit.
[9] The method according to [8], including a step of removing O ₂ from the gas in the gas circuit in the gas circuit in which the gas constituting the gas phase circulates.
[10] The method according to [9], wherein the step of removing O ₂ is a step of bringing a gas constituting the gas phase into contact with the O ₂ absorbent in the gas circuit.
[11] In the gas circuit in which the gas constituting the gas phase circulates, H ₂ is recovered from the gas in the gas circuit, the recovered H ₂ is circulated again in the gas circuit, and the residual gas that could not be recovered The method according to any one of [8] to [10], further including a step of disposing of.
[12] A step of newly supplying at least one gas selected from the group consisting of H ₂ , CO ₂ , and CO to the gas constituting the gas phase in the gas circuit in which the gas constituting the gas phase circulates The method according to any one of [8] to [11], which is additionally included.
[13] including a step of keeping the partial pressure of the volatile component of the gas constituting the gas phase equal to the liquid phase in the gas circuit in which the aqueous medium contains a volatile component and the gas constituting the gas phase circulates [ 8] The method according to any one of [12].
[14] The method according to [13], wherein the volatile component is water and the moisture pressure of the gas constituting the gas phase is kept equal to the liquid phase.
[15] An aqueous medium containing anaerobic microorganisms is partitioned by a filtration membrane that allows permeation of the aqueous medium. The method according to [1]-[4], wherein the gas phase is contacted with the gas phase through the gas permeable membrane.
[16] The method according to [15], wherein the filtration membrane is a microfilter or an ultrafiltration membrane.
[17] The method further includes the step of circulating the aqueous medium in the aqueous medium circuit, wherein the filtrate and the gas phase are brought into contact with each other through the gas permeable membrane in the aqueous medium circuit, and are brought into contact with the gas phase. The method according to [15] or [16], wherein the filtrate is returned to the anaerobic microorganisms retained on the filtration membrane.
[18] The method according to any one of [1] to [4], wherein the aqueous medium containing anaerobic microorganisms contacts the gas permeable membrane while containing the anaerobic microorganisms.
[19] Any one of [1] to [4], wherein the gas permeable membrane is a hollow fiber having the gas permeable membrane as an outer wall, a gas is disposed inside the hollow fiber, and an aqueous medium is disposed outside the hollow fiber. The method described in 1.
[20] The method according to [19], wherein the gas inside the hollow fiber is moved, the aqueous medium outside the hollow fiber is also moved, and the moving directions of both are opposed.
[21] The method according to [19] or [20], wherein turbulent flow is imparted to the aqueous medium flowing outside the hollow fiber.
[22] Anaerobic culture in an aqueous medium comprising (1) H ₂ and (2) one of or both of CO ₂ and CO to produce organic matter, comprising the following components: An apparatus for producing an organic substance for producing the organic substance in the aqueous medium;
(1) A gas permeable membrane that allows permeation of the gas to a gas phase containing at least one gas of H ₂ , CO ₂ , and CO, wherein the aqueous medium is passed through the gas permeable membrane and the other A gas permeable membrane that forms an interface where gas exchange takes place between the two when the gas phase is disposed in
(2) a gas circuit connected to the gas permeable membrane of (1) and circulating a gas constituting a gas phase containing at least one gas of H ₂ , CO ₂ , and CO; and
(3) An aqueous medium circuit that is connected to the gas permeable membrane of (1) and circulates the aqueous medium.
[23] The apparatus according to [22], wherein the gas permeable membrane is a gas permeable membrane made of a hydrophobic material.
[24] Any material selected from the group consisting of polyethylene / PE, polypropylene / PP, polytetrafluoroethylene / PTFE, poly-4 methylpentene 1, and silicone rubber, or a composite material thereof The device according to [23].
[25] Any of [22] to [24], wherein the gas permeable membrane is a hollow fiber having the gas permeable membrane as an outer wall, a gas is disposed inside the hollow fiber, and an aqueous medium is disposed outside the hollow fiber. The device described in 1.
[26] The apparatus according to [25], wherein a plurality of the hollow fibers are packed in a column, and the aqueous medium circulates in the column.
[27] The apparatus according to [25] or [26], wherein a gas circulating inside the hollow fiber is opposed to a circulating direction of an aqueous medium circulating outside.
[28] The apparatus according to any one of [22] to [27], wherein an oxygen absorbent is disposed in the gas circulation circuit. [29] The apparatus according to [28], wherein the oxygen absorbent is a liquid.
[30] The gas circulation circuit additionally includes hydrogen recovery means, and hydrogen recovered from the gas in the gas circulation circuit by the hydrogen recovery means is circulated again to the gas circulation circuit and cannot be recovered. The apparatus according to any one of [22] to [29], wherein the residual gas is discarded.
[31] In the aqueous medium circuit of (3), the permeation of the aqueous medium additionally includes a microorganism holding compartment for holding the anaerobic microorganism cells partitioned by a permissible filtration membrane [22]- [30] The apparatus according to any one of [30].
[32] An organic substance extraction means for collecting organic substances assimilated by the microorganisms accumulated in the aqueous medium from the aqueous medium recovered from the microorganism holding compartment through the filtration membrane is additionally provided in the aqueous medium circuit. The device according to [31].

The present invention comprises (1) H ₂ and (2) anaerobic microorganisms that produce organic substances by assimilating either or both of CO ₂ and CO in an aqueous medium and accumulate in the aqueous medium The present invention relates to a method for producing an organic substance that recovers an organic substance assimilated by a microorganism from the aqueous medium, which includes the following steps.
(a) contacting the aqueous medium with a gas phase containing at least one gas of H ₂ , CO ₂ , and CO through a gas permeable membrane that allows permeation of the gas; Forming an interface for gas exchange with
at the interface of the (b) (a), and H _2, CO _2, and CO and 0 ₂ of the respective partial pressures respectively a1, a2, a3 and a4 in the gas phase, the pressure possessed by the gas contained in the aqueous medium Is b1, b2, b3 and b4, the partial pressure on the gas phase side is maintained at a1> b1, a2> b2, a3> b3, and a4 <b4, and the gas phase is separated from the interface of (a). Absorbing the gas in the aqueous medium and dispersing oxygen in the aqueous medium in the gas phase; and
(c) A step of recovering the assimilated organic matter accumulated in the aqueous medium from the aqueous medium.

In the present invention, anaerobic microorganisms that produce organic substances by assimilating (1) H ₂ and (2) either or both of CO ₂ and CO are used as microorganisms that can assimilate gas resources. For example, anaerobic microorganisms having the following assimilation properties are known.
(1) H ₂ + (2) CO ₂ → [Organic]
(1) H ₂ + (2) CO → [Organic]
(1) H ₂ + (2) CO ₂ and CO → [Organic]
Therefore, any anaerobic microorganism can be used in the present invention as long as the microorganism having the above assimilation property assimilates these gas resources to produce a target organic substance. On the other hand, the aqueous medium in the present invention can be any aqueous medium containing anaerobic microorganisms. In the present invention in which an organic substance is produced using the activity of microorganisms, the aqueous medium is usually a culture solution containing components necessary for the growth of microorganisms and the maintenance of the cells. Growth is synonymous with microbial growth. On the other hand, the maintenance of bacterial cells means that anaerobic microorganisms continue to survive and maintain the activity of producing the desired organic matter.

  In the present invention, the culture solution is also referred to as a fermentation solution because organic substances are produced by fermentation of anaerobic microorganisms. The culture solution containing anaerobic microorganisms can directly contact the gas-liquid interface described later in a state where the anaerobic microorganisms are dispersed. Alternatively, the cells can be held in a membrane that cannot pass through anaerobic microorganisms, and only the culture solution can be allowed to contact the gas-liquid interface. Furthermore, an anaerobic microorganism can be held in an ultrafiltration membrane or a semipermeable membrane through which cells do not permeate, and a gas-absorbing liquid that permeates these membranes can be used as the aqueous medium in the present invention. The aqueous medium carries gas components to be supplied to the anaerobic microorganisms or gas components to be removed from the living environment of the anaerobic microorganisms (that is, inside the semipermeable membrane) between the gas-liquid interfaces described later. At this time, among the medium components for the survival of the anaerobic microorganism, the component having a large molecular weight that does not permeate the semipermeable membrane is retained together with the anaerobic microorganism inside the semipermeable membrane.

The method for producing an organic substance of the present invention comprises (a) an aqueous medium containing the anaerobic microorganism and a gas phase containing at least one gas of H ₂ , CO ₂ , and CO, which allows permeation of the gas. A step of contacting through a permeable membrane to form an interface where gas exchange is performed between the aqueous medium and the gas phase. The interface between the aqueous medium and the gas phase includes not only a mode in which both are in direct contact as long as gas exchange is performed through the interface, but also a case in which the both are in indirect contact through a gas exchange membrane.

  The interface where the gas exchange is performed can be formed by using a gas permeable membrane made of a hydrophobic material, for example. As the hydrophobic material constituting the gas permeable membrane, any material selected from the group consisting of polyethylene / PE, polypropylene / PP, polytetrafluoroethylene / PTFE, poly-4 methylpentene 1, and silicone rubber, or These composite materials can be mentioned. These hydrophobic materials include a material having an opening through which a gas permeates and a material that allows the gas to permeate by diffusion and diffusion of the gas instead of the opening. For example, silicone rubber or the like is a material that does not have an opening and allows gas to permeate therethrough. A preferred gas permeable membrane in the present invention is a gas permeable membrane having an opening on the membrane surface. Examples of the hydrophobic material having the opening include any material selected from the group consisting of polyethylene / PE, polypropylene / PP, and polytetrafluoroethylene / PTFE, or a composite material thereof. As long as these gas permeable membranes have openings inside the membrane, both surfaces or one surface thereof may be covered with a thin film of a gas permeable material.

  In the present invention, the pore size of the porous gas exchange membrane is at least a size through which gas resources can pass, and on the other hand, when an aqueous medium holding anaerobic microorganisms comes into contact with the gas exchange membrane, Any size can be used as long as it does not exceed the size that can maintain the interface. More specifically, the average pore size is usually 0.0005 μm to 5 μm, preferably 0.01 μm to 1 μm, more preferably 0.01 μm to 0.5 μm. The gas exchange capacity of the porous gas exchange membrane used in the present invention is affected not only by the pore size but also by the porosity. In general, the greater the porosity, the greater the gas exchange capacity. On the other hand, since the volume of the membrane material decreases, the strength of the membrane tends to decrease. Therefore, it is advantageous to use a membrane material having a high porosity within a range where the physical structure of the membrane can be maintained in the usage environment. The porosity refers to the ratio (volume ratio) of the opening to the volume of the entire film. Any porous membrane that can be used as a commercially available gas exchange membrane can be used in the present invention. The preferable porosity of the porous membrane in the present invention is, for example, 10 to 90%, usually 15 to 70%, preferably 20 to 50%, and more preferably 25 to 40%.

In the method of the present invention, in addition to the step (a), at the interface of (b) (a), the partial pressures of H ₂ , CO ₂ , CO and 0 _{2 in} the gas phase are set to a1, a2, When a3 and a4 are set, and the pressure of the gas contained in the aqueous medium is set to b1, b2, b3 and b4, the partial pressure on the gas phase side is a1> b1, a2> b2, a3> b3, and a4 < Maintaining b4, the step of absorbing the gas in the gas phase from the interface of (a) into the aqueous medium and dispersing the oxygen in the aqueous medium in the gas phase is included. As already mentioned, the solubility H _2, CO _2, gas resources such as CO or 0 ₂ in the aqueous medium to be removed from the survival environment of anaerobic microorganisms, which requests for anaerobic microorganisms produce organic matter, Each is different. Specifically, CO ₂ and 0 ₂ Whereas easily dissolved in an aqueous medium, H ₂ is low very soluble. The supply of gas resources which have a dissolution properties of such mixed, in order to achieve both removal of 0 ₂ from the aqueous medium, it is necessary conditions defined by the present invention. Each condition prescribed | regulated by this invention can be put together as follows.
Gas phase side Liquid phase side
H ₂ partial pressure (a1)> H ₂ partial pressure (b1)
CO ₂ partial pressure (a2)> CO ₂ partial pressure (b2)
CO partial pressure (a3)> CO partial pressure (b3) and
O ₂ partial pressure (a4) <O ₂ partial pressure (b4)
However, the gas partial pressures on the gas phase side and the liquid phase side usually change continuously with the activity of microorganisms. Therefore, while maintaining the above conditions, there may be a state where the gas phase side and the liquid phase side are temporarily the same gas and have an equal partial pressure. However, if the gas partial pressures in the gas phase and the liquid phase are monitored and efforts are made to maintain the necessary conditions, the situation in which the above conditions are exceptionally excluded is transient. Therefore, such temporary disturbance of conditions is allowed.

By maintaining the above conditions, the gas resources H _2, CO _2, and CO are always one supplied from the gas phase side to the liquid phase side, 0 ₂ is absorbed in the gas phase side from an aqueous medium. In order to maintain the aqueous medium in an environment suitable for the activity of anaerobic microorganisms, the oxygen concentration in the aqueous medium is maintained at, for example, 2.0 ppm or less, preferably 0.5 ppm or less, more preferably about 0.1 ppm. Is desirable. In general, anaerobic microorganisms suitable for the production of organic matter can keep the cells safe by maintaining the oxygen concentration at 0.1 ppm or less, and the influence of oxygen on the production of organic matter can be ignored. An O ₂ concentration of 0.1 ppm in pure water at 25 ° C. corresponds to an O ₂ partial pressure of about 250 Pa. Therefore, when the temperature of the liquid phase is 25 to 35 ° C., the O ₂ partial pressure (a4) in the gas constituting the gas phase is preferably 300 Pa or less, for example, 250 Pa or less. In the present invention, when the O ₂ partial pressure (a4) is normally maintained at 300 Pa or less, for example, 250 Pa or less, when the O ₂ partial pressure in the gas phase exceeds the reference value, the O ₂ partial pressure (a4) is quickly reduced to the reference value or less. including. Therefore, even if the O ₂ partial pressure in the gas phase temporarily exceeds the standard, the O ₂ partial pressure is maintained if it quickly becomes below the standard due to the action of oxygen absorbing means as described later. Is considered. In the present invention, such a condition can be defined as “a state in which oxygen is substantially removed”.

The amount and pressure (partial pressure; partial pressure) of the gas in the aqueous medium will be specifically described. In general, gas dissolution in an aqueous medium is considered to be identical to the behavior in pure water, so it can be assumed that gas dissolution in an aqueous medium at the interface between the aqueous medium and the gas phase obeys Henry's low. . That is, when the weight fraction of each component of the gas contained in the aqueous medium is wi (w1, w2, w3, w4, ......), “the pressure of the gas contained in the aqueous medium” bi ( b1, b2, b3, b4,...) can be expressed by the following formula (1).
[Equation 1]
bi = Mo ・ Ki ・ wi / Mi (i = 1, 2, 3, 4, ...) (Formula 1)
Here, Ki is the Henry constant of the i-th gas component. It is a constant that can be determined from the Henry's constant of each gas, and the solubility value at the temperature T of the i-th gas in water described in Chemical Handbook 5th Edition Basic Edition (Maruzen Co., Ltd.) II-144. In the formula, Mi is the molecular weight of the i-th gas component, and Mo is the molecular weight of water.

Partial pressure of the gas in aqueous medium: partial pressure of bi and gas phase: differential pressure of ai: When there is Δpi, the gas (i) is the one with the higher partial pressure according to Henry's equation (Equation 2) To an equilibrium state (that is, a state where the partial pressures are equal). Specifically, when the partial pressure of the liquid phase (aqueous medium) is low, the gas is absorbed from the gas phase into the liquid phase (aqueous medium) and is in an equilibrium state. Conversely, when the partial pressure on the gas phase side is low, the gas is dispersed from the liquid phase to the gas phase until an equilibrium state is reached.
[Equation 2]
ai = Ki ・ (Mi / Mo) ・ wi ^(ai)・ ・ ・ (2-1)
bi = Ki ・ (Mi / Mo) ・ wi ^(bi)・ ・ ・ (2-2)
Where wi ^(ai) and wi ^(bi) are weight fractions of the i-th gas component at pressures ai and bi.

Further, the differential pressure: Δpi of each gas is derived as follows by Equation 3.
[Equation 3]
Δpi = ai-bi = Ki ・ (Mi / Mo) ・ Δwi (3)
Here, Δwi is the amount of absorption (in the case of a positive value) until reaching equilibrium, or the amount of dispersion (in the case of a negative value).

  However, in the present invention, since it is desirable to prevent gas leaching from the gas permeable membrane to the aqueous medium, it is preferable that the value of Σai−Σbi: ΔP be equal to or less than the capillary pressure for the gas permeable membrane of the aqueous medium. Furthermore, if ΔP is too large, there is a concern that the gas permeable membrane is physically destroyed by pressure, so it is desirable to maintain it within a certain range. Therefore, for example, when a porous membrane made of polypropylene / PP is used as the gas permeable membrane and gas exchange is performed at 30 ° C., ΔP is usually 0.6 MPa or less, desirably 0.3 MPa or less, more desirably 0.1 MPa. It can be as follows. The same conditions are desirable when using a gas permeable membrane other than PP. ΔP can be set to an appropriate condition in consideration of the strength of the film and the temperature condition for carrying out the present invention.

Note that the total pressure on the gas phase side: P (total pressure) is determined by the sum of the partial pressures of the gases constituting the gas phase. In the present invention, H ₂ , CO ₂ , and CO, which are gases to be supplied to the aqueous medium, are positive pressure, and conversely, O _2, which is a gas to be absorbed from the liquid phase, is a negative pressure. Therefore, in order to prevent gas leakage into the aqueous medium and physical destruction of the gas permeable membrane, it is desirable to control the partial pressure of each gas in consideration of the total partial pressure of the gases constituting the gas phase. .

Under the conditions as described above, gas exchange is performed through the interface by bringing the aqueous medium and the gas phase into contact with each other through the gas permeable membrane. The absorption of each gas from the gas phase to the liquid phase or the dispersion from the liquid phase to the gas phase occurs continuously until the differential pressure of each gas reaches 0 (equilibrium state). The differential pressure of each gas, the speed of absorption and dispersion are not constant. For example, CO ₂ having high solubility in an aqueous medium easily reaches an equilibrium state, whereas H ₂ having low solubility often takes time to reach an equilibrium state. In any case, by continuously adjusting the components of each gas in the gas phase according to the characteristics of each gas, gas exchange is continuously performed, and the composition of each gas in the aqueous medium is maintained in an ideal state. be able to.

In the present invention, the substrate gas is assimilated and organic matter is generated by the activity of the anaerobic microorganisms. Therefore, the substrate gas is consumed according to the generation of the organic substance, and the concentration of the substrate gas in the aqueous medium is lowered. Therefore, it is desirable to monitor the partial pressure of the gas on the gas phase side in the present invention and maintain it within a certain range. The gas partial pressure in the gas phase can be monitored using, for example, a known gas sensor. Similarly, the gas partial pressure in an aqueous medium can also be monitored. As a result of monitoring, when a drop in H ₂ , CO ₂ , or CO partial pressure is detected in the gas phase or liquid phase, the gas on the gas phase side is replenished to increase the partial pressure, and into the aqueous medium The amount of supply can be increased.

As mentioned earlier, the solubility of H ₂ in aqueous media is low compared to CO ₂ . Therefore, the gas composition on the gas phase side preferably has a high H ₂ ratio. Specifically, it is preferable to maintain the ratio (molar ratio) of (1) H _{2 in} the gas higher than (2) the total of CO ₂ and CO. More specifically, (1) the ratio (molar ratio) of H ₂ is (2) the same as the total of CO ₂ and CO, preferably 1.5 times or more, more preferably 2 times or more. it can. The CO ₂ and CO supplied to the aqueous medium as the carbon source can be selected according to the assimilation ability of the anaerobic microorganisms that produce the organic matter. For example, even if the anaerobic microorganism to be used is CO assimilating, it is not always necessary to supply CO if CO ₂ alone exhibits a sufficient production capacity of organic matter. Alternatively, when the production of organic matter is improved by supplying both CO ₂ and CO, both can be supplied.

In the present invention, gas exchange is performed locally at the gas-liquid interface. Therefore, even if the average partial pressure of the entire gas phase is maintained higher than that of the liquid phase, the gas exchange is temporarily stopped when the partial pressure near the interface locally reaches equilibrium. However, the gas concentration deviation in the gas phase is eventually eliminated by repeating the equilibrium and diffusion until the average partial pressure of the entire gas phase reaches equilibrium. However, if the gas occupying the gas phase is actively circulated, it is possible to prevent the gas partial pressure in the gas phase from being biased. The gas phase is preferably circulated also when the gas environment in the aqueous medium is maintained by monitoring and adjusting the partial pressure of each gas component in the gas phase. By circulating, the gas in the gas phase is homogenized and gas exchange with the aqueous medium can be performed efficiently. In the present invention, the gas constituting the gas phase can be circulated in a gas circuit cut off from the outside air.
Alternatively, the mixed gas after the gas exchange with the aqueous medium at the gas-liquid interface can be exhausted as it is. The evacuation can be performed continuously or can be discarded by a batch process in which a new mixed gas is replaced every predetermined time.

  The deviation of the gas concentration can occur not only in the gas circuit but also in an aqueous medium. That is, near the interface with the gas phase side, even if the partial pressure of the gas reaches an equilibrium state with the gas in the gas phase, it may not reach equilibrium at a position away from the interface. Therefore, in the present invention, it is preferable to circulate the aqueous medium as well as the gas phase side. When an aqueous medium is also circulated, the relative circulation speed can be improved by making the circulation direction of the aqueous medium and the circulation direction of the gas phase face each other. Improvement of the circulation speed contributes to improvement of gas exchange efficiency. Further, if turbulent flow is added to the aqueous medium and gas, further improvement in gas exchange efficiency can be expected. In particular, it is particularly preferable to generate turbulence in an aqueous medium that is slower to diffuse. Turbulent flow, also called non-unidirectional flow, refers to the fact that an aqueous medium exhibits irregular motion over time. In the preferred turbulent flow, the aqueous medium forms fine vortices having different sizes and rotation directions. For example, if a baffle plate or an obstacle is arranged in the flow direction of the aqueous medium, or if the gas permeable membrane is a hollow fiber shape, a flow perpendicular to the hollow fiber can be created to make the hollow fiber itself an obstacle that disturbs the flow. A flow can be generated.

For example, gas exchange modules composed of gas exchange membranes are commercially available. In a commercially available gas exchange module, a bundle of hollow fibers made of a gas exchange membrane is packed in a column. By adopting a structure in which hollow fibers are bundled, an effective area capable of gas exchange can be increased. The internal space and external space of the hollow fiber in the gas exchange module are communicated only via the hollow fiber surface. Gas exchange is performed between the medium existing on either side of the hollow fiber and the medium existing on the other side via the hollow fiber surface. Usually, these gas exchange modules are often used for one-way gas exchange such as degassing from a liquid medium. However, in the present invention, it has been found that efficient production of organic substances by anaerobic microorganisms can be realized by performing bidirectional gas exchange such as supply of gas resources as raw materials and removal of oxygen in an aqueous medium. It was.
In order to simply supply gas to the liquid phase, the object could be achieved by increasing the pressure on the gas phase side of the membrane contactor. Or conversely, when removing gas from the liquid phase, the pressure on the gas phase side may be kept low. However, in order to perform bidirectional gas exchange, it is necessary to control the partial pressure of the gas constituting the gas phase, not simply controlling the atmospheric pressure. By realizing bi-directional gas exchange using one gas permeable membrane, the present invention has realized a completely new culture environment control method that has not existed before. In other words, it is a major feature of the present invention that the supply of gas resources to the aqueous medium and the removal of oxygen (O ₂ ) from the same aqueous medium are realized through one common gas permeable membrane. In order to perform such bidirectional gas exchange, the gas exchange principle of controlling the partial pressure of the gas to be supplied and the gas to be removed is not anaerobic, rather than simply controlling the total pressure. The present invention is greatly different from known culture techniques in that it is applied to a culture environment of microorganisms.

  When the gas exchange module is used in the present invention, usually, the inside of the hollow fiber can be in the gas phase, and the aqueous medium can be arranged on the outside. Or conversely, an aqueous medium can be arranged inside the hollow fiber, and a gas phase can be arranged outside. And the improvement of both gas exchange efficiency can be anticipated by making both circulation directions oppose. Gas exchange can be performed by extracting a part of the aqueous medium from the culture tank holding the aqueous medium containing the anaerobic microorganisms and supplying it to the gas exchange module. The aqueous medium supplied to the gas exchange module is circulated again in the culture tank after currency in the gas exchange module. By continuously circulating the aqueous medium to the gas exchange module, it is possible to continuously supply gas resources and deoxygenate the aqueous medium. In addition, by adding a part of the liquid returned to the culture tank to the liquid supplied from the culture tank to the gas exchange module, the gas exchange residence time of the culture liquid is increased and the supply liquid flow rate is increased, and the burden on the fermentation tank is increased. Gas exchange efficiency can be increased while reducing the weight. Or after incubating the aqueous medium supplied to the gas exchange module for a fixed time, it can return to a culture tank and gas exchange can also be performed (batch process).

In the present invention, H ₂ , CO ₂ , or CO (which is a raw material for producing organic matter) is supplied to an aqueous medium through a gas exchange membrane, and similarly, from the growth environment of anaerobic microorganisms by gas exchange. Remove ₂ That is, by lowering the O ₂ concentration in the gas phase side, the O ₂ contained in the aqueous medium is diffused into the gas phase side, O ₂ in an aqueous medium is removed. Once even after clearing the O ₂ from the habitat of anaerobic microorganisms, e.g., contact with air, free and oxygen molecules from the culture medium components, such as by oxygen carrying-by media components to be newly replenished, O ₂ is There is always the potential to be brought into an aqueous medium. Therefore, in a preferred embodiment of the present invention, not only supplying a gas phase having a low O ₂ partial pressure but also a step of removing O ₂ contained in the gas on the gas phase side is included. For example, O ₂ removing means can be provided in the gas circuit. For example O ₂ absorber by contacting the gas constituting the gas phase, it is possible to remove O ₂ in the gas phase. Oxygen absorbers are known.

  For example, an oxidation catalyst for removing molecular oxygen can be provided. A steel wool method is known as an oxidation catalyst. In the steel wool method, steel wool (cotton-like iron) brought into contact with acidic copper sulfate or the like is placed inside the gas circuit. Oxygen is rapidly consumed by the action of iron constituting the steel wool and copper on the surface, and molecular oxygen is removed from the inside of the gas circuit. Alternatively, liquid oxygen absorbers are also known. For example, alkaline pyrogallol solution is a powerful oxygen scavenger. For example, a low oxygen environment in the gas circuit can be maintained by passing the gas through the alkaline pyrogallol solution in the gas circuit. The liquid oxygen scavenger is a preferable oxygen scavenger in the present invention because it can be easily brought into contact with the gas phase by an operation such as aeration and can be easily exchanged.

In addition, the gas circuit can be maintained in a state close to water vapor saturation by bringing a gas into contact with the aqueous solution. Gas exchange through the gas permeable membrane occurs with all gases. Therefore, when the water vapor partial pressure on the gas phase side is low, water constituting the aqueous medium may evaporate to the gas phase side and the aqueous medium may be concentrated. When an aqueous solution is used as an oxygen absorbent, not only O ₂ is absorbed, but also an effect of maintaining a high vapor partial pressure on the gas phase side can be expected. Accordingly, an aqueous oxygen absorbent is a preferred oxygen absorbent in the present invention. Alternatively, in addition to the oxygen absorbent, water vapor can be actively supplied to the gas phase side. For example, the gas constituting the gas phase can be passed through water, or water vapor or water droplets can be supplied into the gas phase to keep the water vapor partial pressure high. Furthermore, when there is a volatile component other than water in the aqueous medium, the partial pressure in the gas phase of the volatile component can be made equal to that of the aqueous medium.

In the present invention, H ₂ can be recovered from the gas in the gas circuit and circulated again in the gas circuit, and gases other than H ₂ can be discarded. As stated repeatedly, the solubility of H ₂ in aqueous media is low. On the other hand, the solubility of CO ₂ is remarkably high. Therefore, in practice, the supply of CO ₂ to the aqueous medium is rapidly performed, whereas the supply of H ₂ is delayed. In other words, while CO ₂ reaches equilibrium relatively easily, the H ₂ partial pressure on the gas phase side continues to decrease relatively slowly. The total pressure on the gas phase side is the sum of the partial pressures of the gases constituting the gas phase. When the total pressure of the gas phase has an upper limit, it is reasonable to increase the partial pressure of the gas component that is supplied slowly instead of the gas that is supplied to the aqueous medium quickly. In other words, in the present invention, once a sufficient amount of CO ₂ (or CO ₂ and CO, or CO) is supplied, the partial pressure of the slowest supply of H ₂ is increased instead of these supplied gases. Is reasonable. That is, after CO ₂ (or CO ₂ and CO, or CO) reaches equilibrium, the H ₂ partial pressure can be increased by the amount that these gas partial pressures have decreased. Further, by-products in the aqueous medium are also absorbed on the gas phase side through gas exchange. By-products include components that hinder the activity of anaerobic microorganisms, such as ammonia and hydrogen sulfide generated by the activity of anaerobic microorganisms. Alternatively, an inert gas such as N _{2 is} also absorbed on the gas phase side by gas exchange. The presence of inert gas does not directly contribute to the growth of anaerobic microorganisms. However, in order to perform an effective gas exchange while the total pressure is limited, it is preferable to discard the inert gas.

In the present invention, the recovery of H _2, means the concentration of H _2. That refers to the mixed gas in the gas circuit, and relatively rich in H ₂ fractions, divided into a poor fractionation relatively H _2, that is recycled to the fractionation again in the gas circuit rich in H _2. Here, the “relatively rich H ₂ fraction” is defined as containing more H ₂ compared to the “relatively poor H ₂ fraction”. Therefore, it is not always necessary to separate high purity H ₂ . H ₂ in the mixed gas constituting the gas phase can be recovered by, for example, a hydrogen separation membrane. A membrane capable of separating a gas such as hydrogen from other components by using a material having gas separation ability such as polyimide, cellulose acetate, polysulfone composite membrane, polyamide, or polyetheramide is known. The hydrogen separation membrane is a membrane that selectively separates hydrogen by treating a difference in the permeation rate of gas in the membrane. When used in the present invention, the mixed gas constituting the gas phase is brought into contact with the hydrogen separation membrane, and the pressure on the other side of the hydrogen separation membrane is lowered to selectively recover H ₂ in the mixed gas. can do. The selectivity of the hydrogen separation membrane for hydrogen depends on the difference in the permeation rate of the gas in the membrane. Therefore, it does not necessarily recover only hydrogen, but has sufficient selectivity to obtain a fraction rich in H ₂ . The fraction rich in H ₂ recovered by the hydrogen separation membrane can be circulated as it is in the gas circuit. Alternatively, if necessary, components other than H _{2 can be} further absorbed or adsorbed and then circulated in the gas circuit. If the supply amount into the aqueous medium is reduced due to the disposal of the gas, H ₂ or other gas (that is, CO ₂ and / or CO) can be supplemented as necessary.

In the present invention, “gas other than H ₂ ” includes a fraction that is relatively poor in H ₂ . Therefore, the mixed gas after the recovery of H ₂ by the hydrogen separation membrane is included in the “gas other than H ₂ ” in the present invention. Further, the disposal of gases other than H ₂ means that the gas is once taken out of the gas circuit from the gas circuit. Therefore, not only the taken-out gas is immediately discarded, but it does not prevent the necessary gas from being recovered and circulated again in the gas circuit or used for other purposes. In addition, although means for fractionating H ₂ by physical adsorption using a molecular sieve or the like can be used, a membrane separation method is preferably used in that H ₂ fractionation can be performed easily and continuously.

Processes such as oxygen absorption and H ₂ recovery performed in the gas circuit can be continuously performed on a part of the mixed gas constituting the gas phase. That is, an oxygen absorption circuit branched from a part of the gas circuit can be provided, and a part of the gas constituting the gas phase can be brought into contact with the oxygen absorbent in the circuit. Similarly, a fraction rich in H ₂ can be recovered through the hydrogen permeable membrane in the H ₂ recovery circuit branched from a part of the gas circuit and added again to the gas circuit. Alternatively, the mixed gas can be passed through the oxygen absorbent in the gas circuit. In general, a hydrogen separation membrane has a low O ₂ permeation capability. Therefore, an O ₂ removal effect can also be expected by collecting a fraction rich in H ₂ from the gas phase portion with a hydrogen separation membrane.

In the present invention, the anaerobic microorganisms present in the aqueous medium produce organic substances by supplementarily using the supplied gas resources and the medium components dissolved in the aqueous medium. Therefore, the aqueous medium is maintained in an environment suitable for the growth of anaerobic microorganisms. Specifically, the temperature and pH conditions are adjusted to conditions suitable for the production of organic substances by anaerobic microorganisms. The pH of the aqueous medium may increase and decrease during the continuation of the culture with the supply and consumption of gaseous resources. It is therefore desirable to monitor the pH of the aqueous medium and maintain it at suitable conditions. In order to keep the temperature condition constant, it is desirable to monitor the temperature of the aqueous medium and maintain it at a constant temperature.
The organic matter accumulated in the aqueous medium can be recovered after completion of the culture. Alternatively, during the culturing, a part of the aqueous medium can be taken out and the product can be recovered. The organic matter accumulated in the aqueous medium can be recovered by a known method. The aqueous medium after recovering the product can be reused in the culture system again.

  As described above, in the present invention, gas resources are supplied to microorganisms by gas exchange between a liquid phase (fermented liquid or a filtrate thereof) and a gas phase (gas resources) through a gas permeable membrane, and an anaerobic culture environment. To maintain. Furthermore, the present invention is performed by a method for deoxygenating an aqueous medium (fermented liquid) through the same gas permeable membrane and a gas supply device using the method together with the supply of gas resources. Further, a method for efficiently converting gas resources into organic substances by recovering the gas after the liquid phase contact from the gas supply device, returning the gas resource to the gas supply device again, and circulating the gas, and the method Provide process flow.

In the present invention, in the liquid phase and the gas phase in contact with each other through the gas permeable membrane, the partial pressure of the gas resource component on the gas phase side with respect to the liquid phase side is increased, while gas exchange is performed while keeping the oxygen partial pressure low. Thus, gas supply and deoxygenation treatment are achieved for the fermentation broth. In addition, the present invention further combines one or more separate processes as described below with a process for gas exchange by gas-liquid contact through a gas permeable membrane, thereby further improving the efficiency of gas resources to useful organic matter. Provide a way to build various process flows that convert well. Alternatively, an apparatus for manufacturing a play object is provided, which additionally includes means for performing the following steps.
Adjusting the composition of gaseous components when replenishing gaseous resources consumed by microorganisms;
Recovering gas after gas-liquid contact through the gas permeable membrane,
Circulating the collected gas to a gas processing device;
Replenishing gas resources absorbed in the liquid phase;
Gaseous deoxygenation process, gaseous hydrogen separation process,
A process of creating two or more gases by bypassing the gas;
A step of mixing two or more gases by bypassing the gas;
Adjusting the ratio when separating or mixing two or more gases by bypassing the gas;
A step of continuously or intermittently discharging a part or all of the recovered gas out of the system,
A step of bringing a gas into contact with a solution containing a volatile component contained in the fermentation broth so that the volatile component is contained in the gas,
A step of bringing the gas into contact with the aqueous solution to include moisture in the gas;
A step of filtering the fermentation broth,
Circulating the fermentation liquor or its filtrate to the gas supply device;
A step of installing a fermenter and supplying the fermentation broth to a filtration device or a gas supply device;
Bypassing the fermented liquid or filtrate returned to the fermenter and supplying it to the gas supply device,
A step of taking out organic matter produced by microorganisms from the fermentation broth or its filtrate,
Bypassing the fermented liquid or filtrate returned to the fermenter and supplying it to the gas supply device,

  In addition, in the present invention, when a gas resource capable of maintaining a desired gas partial pressure difference can be continuously supplied to the gas permeable membrane as described above, the gas is not collected and circulated after the gas-liquid contact without being recovered and circulated. Alternatively, a part of the recovered gas can be discharged out of the system continuously or intermittently.

  The aqueous medium to be used for the liquid phase (fermentation liquid) of the present invention is used as it is or a filtrate obtained by filtering out bacterial cells, and absorbs gas resources in a gas permeable membrane and is a deoxygenated liquid as a fermenter. And used for metabolism of microorganisms in the fermentation broth. Moreover, the method and production apparatus which do not have a fermenter and use the liquid phase side space of a gas permeable membrane as a fermenter are also contained in this invention. Moreover, before supplying the filtrate from which the cells have been filtered to the gas supply device, the organic matter produced by the microorganism is supplied to the extraction device or directly to the organic matter separation device, and the organic matter produced in advance by the microorganism is recovered. A method and a production apparatus for supplying the liquid to the gas supply apparatus are also included in the present invention.

<Gas supply method>
The present invention relates to a fermentation method in which a gas resource containing at least carbon oxide (either or both of carbon monoxide and carbon dioxide) and hydrogen is converted into an organic substance using an anaerobic microorganism. The filtrate (aqueous solution: liquid phase) and gas resource (gas phase) are brought into contact with each other, and the partial pressure of the gas resource on the gas phase side is increased and the oxygen partial pressure is decreased with respect to the liquid phase side through the gas permeable membrane. Thus, a gas supply method for maintaining an anaerobic atmosphere of the fermentation broth is provided by absorbing the gas resources in the fermentation broth and supplying them to the cells while absorbing dissolved oxygen in the fermentation broth to the gas phase. . Furthermore, by attaching various additional steps exemplified below, while maintaining the partial pressure difference of the gaseous resource components in contact with the liquid phase, further maintaining the anaerobic atmosphere of the fermentation broth, It is possible to construct a process flow for efficiently converting gas resources to organic materials without waste.
A step of replenishing a gas supply device with a gas component utilized by microorganisms;
Preparing a supplemental gas component;
Collecting the liquid after the gas-liquid contact and circulating it again to the liquid phase;
Collecting the gas after the gas-liquid contact and circulating it again to the gas phase;
A process of performing deoxygenation treatment and / or hydrogen separation treatment in a gas circulation path;
Discharging gas from the gas supply device out of the system,
A step of adding volatilization and / or moisture in advance to the gas supplied to the gas supply device;
Pre-filtering the fermentation broth,
Furthermore, when the gas resource that maintains the above partial pressure difference can be continuously supplied, the gas is not recovered and circulated after contact, and a part of the gas phase is continuously or intermittently discharged out of the system. A method for performing the above-mentioned anaerobic fermentation is provided.

<Organic substance production equipment>
The gas supply in the present invention will be described by taking an organic substance production apparatus: 100 (FIG. 3) as an example. The organic matter production apparatus 100 includes a gas supply apparatus 104 that forms a gas-liquid interface via a gas permeable membrane 104a. By supplying the gas resource: 101 to the gas supply device: 104 to which the fermentation liquid: 102 is circulated and supplied, the gas resource is supplied to the fermentation liquid inside the gas supply device: 104, and the fermentation liquid: 102 It is carried out by an apparatus that efficiently produces useful organic substances such as organic acids and alcohols by microorganisms contained therein. In the process flow exemplified as the organic substance production apparatus: 100 and the organic substance production apparatus: 200 (FIG. 4), the liquid phase part of the gas supply apparatus: 104c and the pipe filled with the fermentation liquid serve as the fermenter: 103. .
Note that the gas 101a that is not absorbed by the liquid phase 104c and has absorbed oxygen from the liquid phase is returned to the gas supply device. Here, oxygen accumulated in gas phase: 104b and excess by exhausting part or all of gas: 101a as waste gas: 101b continuously or intermittently by opening / closing operation of valve: 110e Ingredients can be removed. Alternatively, the waste gas 101b can be discharged out of the system intermittently or continuously by simply supplying the gas resource 101 without collecting and circulating the gas 101a.

The organic matter: 116 produced by the microorganisms accumulated in the fermentation broth: 102 is taken out together with the fermentation broth continuously or intermittently by opening and closing the valves: 110a and 110h. In addition, replenishment of the taken-out fermentation broth and the consumed culture medium is supplied to a gas supply apparatus as supply liquid: 102d. Further, the replenishment of the gas resource 101 can be mixed with the gas 101a at an arbitrary place, instead of being directly performed by the gas supply device.
The organic matter production apparatus: 200 (FIG. 4) will be described more specifically. The organic matter production apparatus 200 shown in FIG. 4 includes a gas phase buffer tank 105 in addition to the organic matter production apparatus 100, and regulates the gas resource 101a to be returned to the gas supply apparatus 104. Furthermore, by filling the gas phase buffer tank 105 with the oxygen scavenger 112, the oxygen absorbed by the recovered gas can be removed. Oxygen absorber: Instead of 112, a volatile component solution or a water solution of an oxygen absorber may be filled in, so that the gas can contain a volatile component or moisture.

  Next, the embodiment of the present invention will be specifically described by taking an organic matter production apparatus: 300 (FIG. 5) as an example. The organic matter production apparatus 300 shown in FIG. 5 includes a fermenter 103 that stores the fermented liquid 102 in addition to the organic matter production apparatus 200. A part of the fermentation liquor: 102 is taken out from the fermenter, and the gas resource: 101 is fed to the gas supply device: 104, and the gas supply device: 104 supplies and desorbs the gas resource to the fermentation liquor. Perform oxygen treatment. Furthermore, the fermented liquor 102a after the processing can be returned to the fermenter 103, or a part or the whole can be intermittently or continuously returned to the gas supply device for circulation. On the other hand, the processed gas resource: 101a is discarded or recovered and returned to the gas supply device: 104 to be circulated.

  Or this invention can also include the structure shown to organic substance production apparatus: 400 (FIG. 6). That is, the organic matter production apparatus 400 shown in FIG. 6 includes a filtration device 106 in addition to the organic matter production apparatus 300. Before taking out a part of the fermented liquid 102 from the fermenter and feeding it to the gas supply device 104, a filtration process is performed by the filtering device 106. The filtrate: 102b is sent to the gas supply device: 104, and the concentrate: 102c is returned to the fermenter: 103.

  Further, in the organic matter production apparatus: 500 (FIG. 7), before the filtrate: 102b filtered by the filtration apparatus: 106 is sent to the gas supply apparatus: 104, microorganisms are produced by the extraction apparatus: 107. The organic substance: 116 is extracted as an extracted liquid: 117 (non-aqueous solution): 115, and the remaining liquid (aqueous solution) is sent to the gas supply device: 104. The extract solution 115 extracted from the extraction device 107 is sent to the organic matter separation device 108 and separated into the extract solution 117 and the organic matter 116 by a known method, and can be recovered respectively. The extraction liquid: 117 is returned to the extraction apparatus: 107 for circulation.

Further, the organic matter production apparatus: 600 (FIG. 8) includes a hydrogen recovery apparatus: 111 in addition to the organic matter production apparatus: 100. A part or the whole of the gas resource 101a to be returned to the gas supply device 104 is sent to the hydrogen recovery device 111 to separate the gas rich in hydrogen and the gas poor in hydrogen. The gas poor in hydrogen is discarded or sent to another process. The gas that is rich in hydrogen is mixed with the recovered gas: 101a that has not been subjected to the hydrogen separation process when part of the gas is subjected to the hydrogen separation process, or the gas supply device as the recovered gas: 101a itself when the whole is subjected to the hydrogen separation process. It is used in the process of collecting and circulating from the factory.
In addition, the component of an organic matter production apparatus shows an example, and an incidental component may be added as needed. Moreover, each component illustrated to organic substance production apparatus: 100-600 can be arbitrarily combined between each illustration except for gas supply apparatus: 104, and can be added or deleted.

<Fermentation liquid sent to gas supply device>
The liquid phase (aqueous medium) to be brought into contact with the gas phase is used by directly removing the fermentation liquid from the fermenter, or using a filtrate obtained by removing cells from the extracted liquid by membrane filtration, etc. Returned to the culture tank. Known methods such as membrane filtration, centrifugal filtration, and filter press can be used as a method for filtering cells from the fermentation broth. A membrane filtration method is particularly suitable. Any membrane can be used as the membrane used for filtration of the bacterial cells as long as the membrane has a pore size sufficiently small to prevent permeation of the bacterial cells. It can be appropriately selected from commercially available microfilters (MF membranes), ultrafiltration membranes (UF membranes), reverse osmosis membranes (RO membranes) and the like. It is also possible to perform multistage membrane treatment by changing the type of separation membrane. The filtration membrane can be appropriately selected according to the composition of the fermentation broth and the type of bacterial cells. For example, an ultrafiltration membrane is preferable because the membrane itself and the membrane module are less clogged by the cells and a high filtration rate can be obtained.
Gas used for contact with the gas phase by removing bacteria and bacteria from the fermentation liquid in advance by removing the bacterial cells from the fermentation liquid in advance using an ultrafiltration membrane, etc. The contamination of the permeable membrane can be further reduced. In the case of membrane filtration, after bringing the filtrate into contact with the gas, part or all of the filtrate is returned to the gas supply device at an arbitrary ratio and circulated again, and mixed again with the filtrate concentrate. Or it can be returned to the fermenter. In addition, a part or all of the concentrated liquid or filtrate obtained by membrane filtration is taken out of the system intermittently or continuously without being returned to the fermenter, and the organic matter produced by the microorganism is recovered. You can also In addition, this operation can be used to adjust the bacterial cell concentration in the fermenter, to dispose of aged cells and accumulated waste products, to remove harmful substances and unnecessary substances accumulated in the fermenter, or to ferment Although it can be used as means for adjusting the liquid composition, it is desirable to carry out it together with the supply of the supply liquid 102d.

  In addition, when returning the fermentation broth or its filtrate to the fermenter, or before bringing the fermentation broth or its filtrate into contact with the gas phase, a process for recovering organic matter assimilated from the gas, or adjusting the pH of the fermentation broth, Add necessary ingredients to maintain fermentation, such as supplemental media and water, replenish new cells, and extract and discard a portion of the fermentation broth or its filtrate, and perform the processes necessary to maintain stable fermentation. be able to.

  When membrane cells or the like are subjected to membrane filtration, which one of filtration and organic matter recovery step is performed first and whether other treatment is performed between them can be arbitrarily selected according to the organic matter extraction method. When including the process of membrane filtration of bacterial cells, etc., the bacterial cells are protected and other treatments including contact with the gas phase can be performed more stably, so the filtrate is converted from contact with gas resources and from gas resources. It is desirable to subject to filtration prior to the treatment of removing the organic matter. When organic substances are taken out by distillation, solvent extraction, membrane distillation, or membrane separation, the amount of gas contained in the fermentation broth or its filtrate is small, and the gas resources to be supplied are delivered to the fermentor without waste. It is preferably performed before the contact treatment with the phase.

<Fermentation liquid filtration module>
There is no restriction | limiting in particular in the shape of the separation membrane used for membrane filtration of a fermented liquor. In order to secure the filtration area of the membrane per treatment liquid, a hollow fiber type membrane module is preferably used. Specifically, it is commercially available and can be arbitrarily selected from membrane modules. The hollow fiber membrane can take a filtration operation method such as cross-flow filtration or back pressure washing in order to prevent the membrane from being soiled or the blockage of the flow path, and is preferably performed in the filtration treatment of the fermentation broth. In addition, supplying liquid to either the inside or the outside of the hollow fiber membrane and supplying gas to the other side can be arbitrarily selected. Even when liquid is supplied to the outside of the hollow fiber membrane, the module structure that accommodates the hollow fiber membrane can be devised to cause turbulent flow in the liquid flow and perform mass transfer between gas and liquid with high efficiency. Can do.

A preferred membrane filtration method is, for example, a cross-flow filtration method in which a hollow fiber (hollow fiber) type ultrafiltration membrane of polysulfone or polyethersulfone is used and a fermentation broth is passed inside the hollow fiber membrane. Moreover, in order to separate low molecular organic substances such as organic acids and alcohol produced from microorganisms and to obtain a sufficient filtration rate, an ultrafiltration membrane having a fractional molecular weight of 30,000 to 150,000 is preferably used as the membrane performance. .
Furthermore, the filtration device: 106 removes the membrane dirt by a known method such as back pressure washing or chemical washing by stopping the liquid supply to the gas supply device or switching the plurality of filtration devices and continuing the operation. It is desirable to maintain filtration performance.

<Gas constituting the gas phase to be supplied to the gas supply device>
In the present invention, as gas resources that anaerobic microorganisms can use as metabolic resources, at least carbon oxide (either carbon monoxide and carbon dioxide, or both) and hydrogen are contained, and these gases are microbial cells. It is taken up as a resource, metabolized, and assimilated into organic matter. Here, the gas resource includes at least carbon oxide (either or both of carbon monoxide and carbon dioxide) and hydrogen. The gas constituting the gas phase is allowed to contain additional gases in addition to the gaseous resources. For example, water vapor, ammonia, etc. may be contained. Furthermore, it is allowed to contain sulfur oxides such as sulfur dioxide, nitrogen oxides such as nitrogen dioxide, and inert gases such as nitrogen and argon as long as they do not inhibit the growth of bacterial cells. The However, it is necessary to suppress the oxygen content in the gas when contacting the liquid phase (aqueous solution: fermented liquid or filtrate thereof) within the range in which the anaerobic atmosphere of the culture liquid can be maintained.

In the present invention, the gas resource can be prepared by gasifying various organic wastes. As the organic waste, for example, the following can be used.
Raw garbage,
Food processing waste,
Fermented waste and its drainage,
sewage,
Sludge, etc.
Organic waste generated from daily life and industry such as combustible waste,
Plant-derived hydrocarbon sources such as cultivated plants and straw after harvesting timber, waste materials, grains and fruits,
Gas (synthetic gas) generated from these various biomass raw materials in a gasifier can be used. Edible or non-edible agricultural products such as cereals, fruits, seeds, cotton, and fibers can be used as gas raw materials, but organic waste is preferably used from the viewpoint of effective use of resources.

On the other hand, hydrocarbon sources derived from so-called fossil fuels such as hydrocarbon compounds, natural gas, coal tar, asphalt, soot, synthetic rubber, naphtha, petroleum or coal are used as gases or pyrolyzed gases. A gas (synthetic gas) obtained from a gasification furnace can also be used as a gas (partial oxidation gas) generated by burning while adding a sufficient amount of oxygen. In this case, since the composition of the raw material is relatively stable, the composition of the gas resource generated therefrom is also relatively stable, which is preferably used in terms of facilitating microbial fermentation management.
In addition, a gas (synthetic gas) obtained by an aqueous shift reaction in which water or water vapor reacts with these synthesis gases can be preferably used because it can newly generate or increase the composition of gas resources, particularly hydrogen components. it can. The water shift reaction is a reaction called water gas conversion or water gas modification, and generates CO ₂ + H ₂ from CO and water vapor as follows.
CO + H ₂ O → CO ₂ + H ₂
Furthermore, a hydrocarbon source obtained by arbitrarily mixing organic waste, edible or non-edible agricultural products, and a fossil fuel-derived hydrocarbon source can be used as a raw material for the gasifier.

  These are collectively referred to as gas resources (syngas) in the present invention, and can be stably obtained as a mixed gas containing at least carbon monoxide and / or carbon dioxide and hydrogen, and a gas that can be industrially obtained in a coherent amount. desirable. It is also possible to adjust these to a gas resource composition more suitable for the present invention by further performing operations such as reforming and separation. Moreover, mixing the obtained synthesis gas and carbon monoxide, carbon dioxide, or hydrogen generated from another gas generation source at an arbitrary ratio can be suitably used as a method for adjusting the composition of the gas resource. In addition, another gas resource, for example, a component contained in waste gas, particularly carbon monoxide or carbon dioxide, is fixed as an organic substance, and means for reducing the total amount of carbon dioxide released into the atmosphere including another gas generation source. When used as, it is preferable to use a mixture of synthesis gas and another gas resource from the viewpoint of environmental protection.

  In addition, waste gas discharged from plants such as oil refining, carbon black, coke, ammonia, and methanol production can be used as a gas resource. When the waste gas is used as a gas resource, the exhaust gas can be used as it is or in place of the synthesis gas by adjusting the composition. In particular, waste gas rich in carbon monoxide or hydrogen can be used as it is or as an aqueous shift reaction, as a gas resource rich in hydrogen, as it is or after adjusting the composition, or as another gas resource according to the present invention. It mixes with the gas obtained from the generation source, and is used suitably as a gas resource of this invention.

In addition, in a charcoal production furnace, a coke oven, a carbon fiber production furnace, etc., waste gas generated when a product is produced by firing or incomplete combustion (steaming) can be used as a gas resource. Alternatively, it is possible to use waste gas when incinerating synthetic rubber products such as waste tires, which are easily incompletely burned, as a gaseous resource. Expected to reduce emission.
However, the waste gas produced by these incineration often contains a large amount of oxygen. When used as a gas resource of the present invention, it is necessary to sufficiently deoxygenate.

In thermal power generation, energy efficiency has been improved by introducing coal gasification combined power generation in which fossil fuel such as coal is gasified without being burned as it is or combined cycle power generation using natural gas as fuel. The surplus gas and waste gas generated for optimizing these power generations can be used effectively as the gas resource of the present invention. Further, in the process of gasification, contaminants such as mercury contained in coal can be removed in advance. Furthermore, sulfur contained in the fossil fuel can be taken out as hydrogen sulfide (H ₂ S) in the process of gasification. Sulfur in fossil fuels causes sulfur compounds that are generated with combustion. The gasification technology having these characteristics is also evaluated as a technology for preventing the release of pollutants to the environment in a thermal power plant or the like. A gasification furnace for thermal power generation can be expected as a useful gas resource generation source of the present invention.

  As described above, the composition of gas generated by various gasification methods varies depending on the type of hydrocarbon source to be gasified. Therefore, if necessary, carbon monoxide and / or carbon dioxide and hydrogen can be purified and then contacted with an anaerobic microorganism. Here, the carbon monoxide and / or carbon dioxide and hydrogen to be brought into contact with the anaerobic microorganism can contain other components as long as they do not interfere with the production of the organic substance by the anaerobic microorganism. For example, methane, nitrogen, and components that are predicted to be generated as by-products in the process of gasification do not affect anaerobic microorganisms. Therefore, it is permissible to collect the gas resources and bring them into contact with anaerobic microorganisms in a state containing these components. Further, for example, a gas resource generated when gasifying asphalt as a hydrocarbon source does not contain oxygen at a level that affects anaerobic microorganisms, and has a composition that can be supplied to a fermenter as it is. However, it does not preclude performing desulfurization, denitration, purification, component adjustment, etc. as necessary.

In the anaerobic microorganism used in the present invention, it is necessary that the gas used for metabolism contains at least carbon monoxide and / or carbon dioxide and hydrogen. In general, the molar ratio of carbon monoxide and / or carbon dioxide and hydrogen necessary for metabolism of bacteria producing organic substances is 1: 1 or more, preferably 1: 2 or more for organic acids, and 1: 3 or more for alcohols. If it exists, there exists a possibility that carbon dioxide may be excessively supplied among the gas resources to supply, and may not be utilized for a microbial cell but may accumulate in a fermenter or circulating gas. For example, in an aqueous shift reaction in which carbon monoxide obtained from a gasifier is reacted with water, a mixed gas having a molar ratio of carbon dioxide and hydrogen of 1: 1 is obtained from 1 mol of carbon monoxide and 1 mol of water. It is done. For this reason, when acetic acid is produced in the cells using only the gas obtained by the aqueous shift reaction as a gaseous resource, carbon dioxide becomes excessive.
2CO ₂ + 4H ₂ → CH ₃ C00H + 2H ₂ 0

  In addition, it is contained as a gaseous impurity and is partly metabolized, but it does not consume cells with components that are partially metabolized but have a low metabolic rate, such as ammonia, nitrogen compounds, sulfur compounds, phosphorus compounds, or inert gases such as nitrogen. Components that are not consumed in the fermenter accumulate as gas components and lower the partial pressure of gas components that are metabolized by microorganisms. In addition, even if the concentration is initially below the cell growth inhibition concentration, a small amount of impurities in the gas accumulates in the fermentation tank over time, causing the growth inhibition of the cell, thereby reducing the efficiency of fermentation. There is also. In particular, when the gas after gas-liquid contact is collected and circulated and supplied, a part or all of the circulating gas is continuously or temporarily discharged out of the system and replaced with new gas resources. In order to prevent accumulation on the gas phase side, it is necessary to adjust the composition of the gas phase so that the partial pressure of the gas to be discarded in the liquid phase (fermented liquid or its filtrate) is higher than that on the gas phase side. Furthermore, the partial pressure of unnecessary gas on the gas phase side is lowered by discharging a part or all of the gas phase side continuously or intermittently outside the system and replacing it with a new gas resource. As a result, an unnecessary gas contained in the liquid phase (aqueous medium) can be moved to the gas phase side, which is effective for preventing accumulation of excessive or unnecessary gas components in the fermentation broth. .

Carbon dioxide is often contained in industrially obtained gas resources in the same amount as hydrogen or in excess. Therefore, it is separated in advance and adjusted to an appropriate gas composition, or carbon dioxide or hydrogen separation means is provided in the circulation gas path, and part or all of the circulation gas is separated and contacted with the liquid phase again. It is preferable to keep the composition of the gas resource appropriate. At this time, the separated excess carbon dioxide may be discarded. However, it is also possible to suppress the release of carbon dioxide into the environment by embedding and isolating carbon dioxide in the ground.
The hydrogen separation treatment can be performed by a known means such as a cryogenic separation method, an adsorption method, or a membrane separation method, but a membrane separation method with less temperature and pressure fluctuation is preferably used. As gas separation membranes, ceramic membranes are commercially available from Noritake, and polyimide and polyamide organic polymer membranes are commercially available from Monsanto and Ube Industries.
In addition, carbon monoxide (only when cells are not metabolized), ammonia, sulfur oxide, nitrogen oxide, etc., after removing part or all of the circulating gas by providing removal means in the circulating gas path It is preferable to keep the composition of the gas resource appropriate by bringing it into contact with the liquid phase again.

  The anaerobic microorganism used in the present invention grows and produces valuable materials if the fermentation broth contains at least carbon monoxide and / or carbon dioxide and hydrogen. There is no. However, the molar ratio of carbon dioxide and hydrogen required for the production of organic substances is 1: 1 or more, preferably 1: 2 or more for organic acids, and 1: 3 or more for alcohols. , At least the same amount as that of carbon monoxide and / or carbon dioxide, preferably 2 times or more. Therefore, for example, by discharging excess carbon monoxide and / or carbon dioxide out of the system, hydrogen equivalent to carbon monoxide and / or carbon dioxide is supplied to produce organic matter. You can also.

  In the present invention, anaerobic microorganisms grow using the reduction energy of hydrogen in metabolism to produce valuable materials. In order to more efficiently produce valuable materials by fermentation of anaerobic microorganisms, it is desirable to effectively ingest and metabolize hydrogen into the cells. In particular, in the gas resources that come into contact with the gas-liquid interface, hydrogen has a low solubility in water and its absorption in the liquid phase at the gas-liquid interface is much lower than that of carbon monoxide and / or oxygen dioxide, especially carbon dioxide. High fermentation efficiency can be obtained by increasing the composition ratio of hydrogen and maintaining a hydrogen partial pressure higher than that of carbon dioxide. On the other hand, it is also known that if the hydrogen concentration in the fermentation broth becomes too high, cell growth is inhibited. However, in reality, under normal conditions, it is rare that hydrogen is supplied in excess so that the problem of excess hydrogen occurs. In the present invention, if the upper limit of hydrogen in the gas resource on the gas phase side is taken into consideration, the hydrogen partial pressure with respect to carbon dioxide in the gas resource at the time of gas-liquid contact through the hydrophobic gas permeable membrane is 2 to 1000 times. In the following, it is preferably 3 times or more and 300 times or less, more preferably 10 times or more and 150 times or less, and further preferably 30 times or more and 60 times or less.

  It is also possible to increase the efficiency of gas exchange at the gas-liquid interface, increase the liquid phase concentration of the gas resource, and promote deoxygenation by making the total pressure of the gas resource relative to the liquid phase higher than the liquid phase. is there. In this case, the relative pressure difference between the liquid phase and the gas phase is preferably 0.5 to 4 times, more preferably 0.8 to 3 times, and even more preferably 1 to 2 times. If the pressure difference between the two phases becomes too large, particularly when a microporous membrane is used as the gas permeable membrane, the gas-liquid interface cannot be maintained, and gas in the gas phase may enter the liquid phase. Otherwise, the gas permeable membrane is destroyed by pressure, the gas is ejected into the liquid phase, the membrane module is broken, etc., and the gas supply device cannot be operated stably, and the foaming in the fermenter and the pressure rise in the vessel are stable. The problem of disturbing fermentation occurs.

The fermented liquid or the filtrate after the gas-liquid contact takes up gas resources to a substantially saturated or supersaturated concentration. For this reason, foaming may occur in association with flow such as return or stirring of the tank. Foaming itself does not affect organic production or anaerobic microorganisms. However, the productivity of organic substances may be reduced when cells rise by flotation (floating). Therefore, it is desirable to transfer the fermentation broth as gently as possible. Conversely, it is preferable to avoid the following handling, for example.
* Stir the fermenter at high speed.
* Liquid feeding process at high flow rate * Dropping the returned liquid in a culture tank

Therefore, although it depends on the shape of the stirring blade used in the fermenter, if it is a normal paddle blade, stirring sufficient to prevent sedimentation of the suspension at 1000 rpm or less, preferably 500 rpm, more preferably 250 rpm or less is sufficient.
In addition, the fermented liquid is preferably sent in an amount of 1 to 10,000 ml / min, more preferably 5 to 1000 ml / min, and even more preferably 5 to 500 ml / min with respect to 100 ml of the fermented liquid. If the amount of circulation is small, the recovery efficiency of the organic matter is lowered, and if the amount of circulation is large, the operation energy of the pump tends to be wasted or the stability of the fermentation liquor tends to be poor.
Furthermore, from the viewpoint of suppressing foaming and pressure pulsation as much as possible, the type of pump used for feeding liquids is not susceptible to high shear at low pressure, such as peristaltic pumps, piston pens, diaphragm pumps, and Mono pumps, and the cells are damaged or foamed by cavitation. It is preferable to select from pumps selected from liquid feeding means that are unlikely to occur.

  In the present invention, in order to keep the hydrogen partial pressure at the gas-liquid interface higher than that of carbon dioxide, it is not always necessary to increase the hydrogen concentration of the composition of the gas resource itself from the beginning. In a preferred embodiment of the present invention, the gas resource recovered after the first gas-liquid contact treatment is recovered and supplied again to the gas-liquid interface. If the gas resource circulates and repeats the gas-liquid contact, the concentration of carbon dioxide that is more easily absorbed in the aqueous solution decreases on the gas phase side, and the concentration of carbon monoxide and hydrogen, particularly hydrogen, gradually increases. For this reason, on the liquid phase side, the carbon dioxide concentration rises to a partial pressure equal to that of the gas phase while the hydrogen concentration is substantially maintained. In other words, the carbon dioxide concentration on the gas phase side is lowered to reach equilibrium. For this reason, although all components are reduced from the circulated gas by an amount commensurate with the amount consumed by the cells in the fermenter, the carbon dioxide consumption in the fermenter is less than the hydrogen consumption. On the phase side, the partial pressure of carbon dioxide will exceed that of hydrogen. As a result, unless additional gas resources are added to the circulating gas resources, the partial pressure of carbon dioxide only decreases on the liquid phase side, and on the gas phase side, carbon dioxide is always slightly higher than the liquid phase. The partial pressure is kept high for hydrogen. This is because the hydrogen that can be used by the cells of the present invention is hydrogen absorbed in the fermenter, and the hydrogen supplied to the gas phase cannot be consumed immediately. The absorption of hydrogen by the fermentation broth includes dissolution of hydrogen in the fermentation broth or hydrogen in a bubble state floating in the fermentation broth.

Therefore, carbon dioxide and hydrogen will be gradually metabolized and consumed by the cells, unless hydrogen gas continues to be supplied to the circulating gas resource in a considerable amount that significantly exceeds carbon dioxide. Since the absorption into the phase is rate limiting, the composition of the circulated gas will reach equilibrium with a greatly increased hydrogen concentration compared to the original feed composition.
On the other hand, when replenishing gas resources to the circulating gas, the composition of the circulating gas must be maintained at a higher partial pressure of carbon dioxide and hydrogen than the liquid phase. And the composition and amount of the circulating gas after contact with a part or all of the gas-liquid contact that is temporarily or continuously discharged out of the system from the circulating gas.

  It should be noted that hydrogen separation means is provided in the circulation path to collect hydrogen and mix it with the recirculation gas to discharge one separated carbon dioxide, absorbed oxygen, inert gas, and impure component gas out of the system. As a result, even when the hydrogen concentration of the supplied gas resource is not sufficiently high, the hydrogen concentration of the mixed gas of the replenished new gas resource and the recovered and circulated gas can be maintained high and accumulated. It is more preferable because it can be prevented from being discharged out of the system together with excess carbon dioxide.

  In order to keep the composition of the gas components contained in the culture broth appropriately, some or all of the gas present above the liquid level of the fermenter is continuously or temporarily discharged out of the system to produce new gas. It can be replaced with resources. In particular, it is important for the stable operation of the fermenter that the gas existing above the liquid level of the culture tank to be discharged and the supply of new gas resources to serve as pressure adjustment of the culture tank. Furthermore, most of the gases other than the inert gas react with water in an aqueous solution, or are converted into inorganic salts by a culture solution component or a pH adjuster, so that anaerobic microorganisms cannot be used. For example, carbon dioxide is converted to carbonate or carbonate. Discharge part or all of the culture solution continuously or temporarily out of the system for the purpose of removing inorganic salts accumulated without being used by the cells and substances that inhibit the growth of dissolved cells. It is also important to replenish the fermenter with a new culture solution for purposes other than reducing the culture solution in order to replenish resources necessary for cell metabolism.

  Since the microorganisms used in the present invention are anaerobic, the gas resource to be supplied needs to have a low oxygen concentration. Therefore, a gas resource originally containing only a low concentration of oxygen is used, or a deoxygenation treatment is performed in advance. It is desirable to use the applied gas resources. However, since a very small amount of oxygen is inevitably contained in the gas resource, it accumulates in the gas in the process of circulating and using the gas resource, or is absorbed in the culture solution and accumulated in the culture tank. In addition, since oxygen may be generated from the supplemented culture medium or the feed water or from the fermentation broth, maintaining the oxygen concentration in the culture broth is a very important operation for managing fermentation. .

  In the conventional method, it was necessary to add an oxygen scavenger such as cysteine to the fermentation broth and maintain it at an appropriate concentration. On the other hand, in the present invention, the fermented liquid (aqueous solution: liquid phase) and the gas resource (gas phase) are brought into contact with each other through the hydrophobic gas permeable membrane, and the liquid phase side is maintained at the interface maintained by the hydrophobic microporous membrane. By increasing the partial pressure of the gas component on the gas phase side and decreasing the oxygen partial pressure, gas resources are supplied to the fermentation broth, and dissolved oxygen in the fermentation broth is absorbed into the gas phase. In this way, by supplying gas resources while maintaining the anaerobic atmosphere of the fermentation broth, dissolved oxygen can always be absorbed from the fermentation broth to the gas phase side, so deoxidation treatment of the culture broth is added to the culture broth It was possible without. However, this does not prevent the fermentation liquor from containing a certain amount of oxygen scavenger for more strict anaerobic management.

<Gas supply device>
In the present invention, a degassing membrane module conventionally used as a degassing membrane for liquid such as water can be used as it is for the gas supply device 104 having a hydrophobic microporous membrane. For example, “Liqui-Cel” (registered trademark) of Celgard and “SEPAREL” (registered trademark) of DCI are listed.
For example, in degassing water, degassing is performed by placing water to be degassed in one of the membrane modules and setting the opposite side to a negative pressure. However, in the present invention, it is necessary to supply a large amount of gas resources to the aqueous medium to be deoxygenated. When the gas assimilated by the anaerobic microorganisms is dissolved, the gas resource dissolved together with the dissolved oxygen is also degassed from the liquid in the normal degassing process in which the negative pressure is simply set. As a result, it is necessary to dissolve the gas resource again after the deoxygenation treatment. In addition, since the gas removed from the aqueous medium contains oxygen, it cannot be reused as it is. Therefore, it is important to cause gas exchange under the specific conditions provided by the present invention.
In particular, the anaerobic microorganism used in the present invention requires hydrogen. The solubility in water is higher for oxygen than for hydrogen. Therefore, if the hydrogen partial pressure on the gas phase side is not sufficiently high, deoxygenation treatment due to the partial pressure difference cannot be performed, or the same amount or more of hydrogen moves from the liquid phase to the gas phase simultaneously with oxygen.

  In the present invention, while using the same degassing membrane, the partial pressure of the gas component on the gas phase side is higher than the liquid phase side, and the oxygen partial pressure is lowered, thereby preventing the degassing of the gas resources, Can be degassed from the aqueous medium. According to the present invention, it is not necessary to add an oxygen scavenger to the fermentation broth and maintain it at an appropriate concentration, and the oxygen scavenging treatment can be performed efficiently. In addition, in order to keep the anaerobic state of the fermentation broth more reliably, even when an expensive deoxygenating agent such as cysteine that has been conventionally used is added to the culture solution, the deoxidizing agent is hardly consumed, It is no longer necessary to add to maintain the concentration.

  As the gas resource used in the present invention, it is desirable to use a synthesis gas having a composition in which the partial pressure of the gas resource is high and the oxygen partial pressure is low with respect to the dissolved gas partial pressure of the liquid phase (fermented liquid or filtrate thereof). Here, the partial pressure of the gas resource is high that the partial pressure of at least one gas selected from the group consisting of carbon monoxide, carbon dioxide, and hydrogen is higher than the partial pressure of the gas in the liquid phase. Say. For this purpose, it is possible to use a gas which has been subjected to deoxygenation treatment in advance to increase the partial pressure of the gas resource and adjust the oxygen partial pressure to be low. However, in the present invention, the partial pressure difference with respect to the liquid phase of each gas component at the interface maintained by the hydrophobic gas permeable membrane where gas exchange is performed is important, and in the environment where the gas and the liquid are in contact, the dissolved gas in the liquid phase As long as the partial pressure of the gas resource is higher than the partial pressure and the oxygen partial pressure is kept low, the composition of the gas resource does not matter.

In particular, when the gas that has come into contact with the fermentation broth but has not yet been absorbed by the liquor is recovered and is again brought into contact with the liquor to effectively supply gas resources to the fermentation broth, deoxidation treatment is performed in this gas circulation step. This is important for effective utilization of gas resources. The deoxygenation treatment can have any known method such as gas absorption, gas adsorption, combustion, and oxygen selective permeable membrane. Further, even when an oxygen scavenger is used in gas absorption, it is not necessary to consider microbial toxicity because it is not necessary to add a drug to the culture solution in the present invention. Therefore, a wide range of oxygen scavengers such as reducing agents such as sodium sulfide, hydrosulfad, sodium sulfite, sodium hydrogen sulfide, hydrazine, reducing metal fine powder such as iron powder, iron wire (steel wool), copper powder, activated alumina, etc. Can be used.
For example, when steel wool is used, steel wool (cotton-like iron) brought into contact with acidic copper sulfate is filled in the gas phase buffer tank, and the action of iron constituting the steel wool and copper on the surface thereof. It can quickly absorb oxygen and remove oxygen from the circulating gas resources.

The gas resource used in the present invention is a gas containing at least carbon oxide (either or both of carbon monoxide and carbon dioxide) and hydrogen. As mentioned above, the difference in solubility of these gases in aqueous solutions is very large. As a result, the amount of carbon dioxide contained in the gas once recovered after contact with the aqueous medium (fermented liquid) is much smaller than that of hydrogen. Even if an oxygen absorbent such as hydrazine that reacts with carbon dioxide is used, a substantial deoxygenation effect can be obtained. Moreover, if reducing gas, such as carbon monoxide and hydrogen sulfide, is added to the gas resource to the extent that the growth of microorganisms is not hindered, it acts as a deoxidizer for the culture solution.
In the present invention, the new gas resource mixed to replenish the gas absorbed in the liquid phase is mixed with oxygen as long as the partial pressure of the gas component after mixing satisfies the partial pressure difference described above. Permissible. It is desirable that the gas is replenished before the deoxygenation treatment and the mixed gas is deoxygenated after the replenishment. Alternatively, if the oxygen concentration of the gas resource to be replenished is sufficiently low, it may be replenished after the deoxygenation treatment of now gas.

  In the present invention, gas exchange is performed by contacting a gas having a composition having a high partial pressure of gas resources and a low partial pressure of oxygen with respect to the dissolved gas partial pressure of the liquid phase (fermented liquid or filtrate thereof) in the liquid phase. . It is not essential to collect and circulate the gas after the gas exchange, and it can be discharged out of the system without being reused.

  In the present invention, the oxygen concentration in the fermentation broth is desirably maintained at 1 ppm or less, preferably 0.5 ppm or less, more preferably 0.1 ppm or less, in order to prevent growth inhibition of anaerobic microorganisms used for fermentation. That is, it is desirable to adjust the conditions so that the oxygen concentration on the liquid phase side can be maintained at this condition through gas exchange between the liquid phase and the gas phase. For this reason, according to the capacity of the fermenter, various conditions such as the amount of liquid extracted from the fermenter to the gas exchange process, the gas exchange area (area of the hydrophobic gas permeable membrane), the supply rate to the gas permeable membrane module, etc. are determined. . For example, the supply ratio of the gas resource and the fermented liquid to the gas supply device is preferably 0.2 to 20 gas amount / liquid amount / minute. Furthermore, the oxygen concentration in the gaseous resource supplied as the gas phase must be set lower than the oxygen partial pressure in the fermentation broth or its filtrate. Specifically, the oxygen concentration in the gas phase is usually 3000 Pa or less, preferably 1000 Pa or less, more preferably 500 Pa or less, more preferably 250 Pa or less.

  Furthermore, the gas resource used in the present invention can contain water vapor. When it is below saturated steam with respect to a fermented liquor or its filtrate, the water which comprises an aqueous medium to gas resources will be absorbed as water vapor. As a result, when the gas resource after gas-liquid contact is discharged out of the system, dehydration gradually occurs from the fermenter. In this case, in order to maintain the composition of the fermentation broth stably, it is desirable to replenish the aqueous medium with water. On the other hand, when the gas that has not been absorbed after the gas-liquid contact is collected and circulated, the moisture content of the gas resource is maintained by the saturated water vapor pressure of the fermentation liquid or its filtrate by the gas circulation. However, when the deoxygenation treatment is performed in the circulation path, the moisture in the gas phase may react with, absorb, and condense with the deoxygenating agent, thereby reducing the deoxygenation efficiency. In this case, it is possible to remove moisture by condensation by cooling or adsorption by molecular sieves prior to the deoxygenation treatment. The removed water is usually discarded. However, water can be collected and returned to the culture tank, or can be mixed as water vapor with the deoxygenated gas resource. Desirably, an oxygen scavenger is dissolved in an aqueous solution and brought into contact with a gas resource by a method such as diffused diffusion or a wet wall to perform a deoxygenation treatment for keeping the amount of water in the circulation path of the recovered gas constant. In this case, the oxygen scavenger is preferably a reducing agent having low reactivity with carbon dioxide, and examples thereof include a sodium sulfide aqueous solution and an iron powder suspension.

The gaseous resource in the present invention can include organic vapor produced by anaerobic microorganisms. When the partial pressure of the organic substance on the gas phase side is low with respect to the aqueous medium (fermented liquid), the organic substance is also absorbed by the gas resource. For this reason, when the gas resource after gas-liquid contact is discharged out of the system, organic matter is gradually lost from the fermenter. That is, it means loss of organic matter produced by fermentation, which is not preferable.
On the other hand, when the gas that has not been absorbed after gas-liquid contact is collected and circulated, the amount in the gas resource is maintained by the saturated vapor pressure of the organic matter in the fermentation liquid or its filtrate by circulation of the gas. However, when a deoxygenation treatment is installed in the circulation path, as in the case of the water vapor described above, there is a possibility that the organic vapor reacts with, absorbs and condenses with the deoxygenating agent, thereby reducing the deoxygenation efficiency. In this case, prior to the deoxygenation treatment, it can be removed by condensation by cooling or adsorption by molecular sieves. Desirably, a substance that is not affected by the organic product produced can be selected as the oxygen scavenger.

  In particular, when highly volatile organic substances such as ethanol, ethyl ether, acetone, ethyl acetate, etc. are the products of microorganisms, the organic substances are added as vapor before the gas resource is brought into gas-liquid contact. By making the organic substance partial pressure equal to the liquid phase partial pressure, the outflow to the gas phase side can be prevented. In this case, highly volatile organic substances can be easily condensed by cooling, etc., and can be evaporated again by simple heating. Therefore, the organic substances evaporated before gas-liquid contact are mixed with gas resources, and gas-liquid contact By condensing and collecting later, it can be incorporated into the circulation path of the gas resource without waste. Further, even when the gas after gas-liquid contact is released out of the system, it can be recovered in the same manner. Recovery is effective to prevent loss of produced organic matter. In particular, when the boiling point of the organic substance is lower than that of water, the outflow to the gas phase due to gas-liquid contact becomes large, so that loss in the gas resource supply process can be prevented and microbial products can be recovered without waste. It is very effective.

<Bacteria contained in fermentation broth>
In the present invention, anaerobic microorganisms that assimilate carbon monoxide and / or carbon dioxide and hydrogen to produce acetic acid can be used. For example, it is known that a microorganism classified into a genus selected from the following group has an ability to produce organic matter by including acetic acid in a metabolic pathway.
Acetobacterium genus Clostridium genus Eubacterium genus Bacteroides genus Sporomusa genus Acetogenium genus Moorella

  Therefore, a microorganism selected from microorganisms classified into these genera, containing acetic acid in the metabolic pathway by anaerobic fermentation using hydrogen and carbon monoxide and / or carbon dioxide, and producing acetic acid and / or ethanol is Preferred microorganisms in the invention. Among them, microorganisms belonging to the genus Acetobacterium, the genus Clostridium, or the genus Moorella are preferable as microorganisms having the ability to produce acetic acid in the present invention. It is confirmed that microorganisms produce acetic acid by lowering the pH of the culture or by anaerobically culturing the microorganisms in the presence of hydrogen and carbon monoxide and / or carbon dioxide, and detecting the acetic acid produced in the culture. can do. More specifically, for example, the following microorganisms can be used as microorganisms in the present invention.

Acetobacterium sp. No.446, FERM P-7017
(Acetobacterium sp. No.446, FERM P-7017)
Acetobacterium sp. MA-1, FERM P-8676
(Acetobacterium sp. MA-1, FERM P-8676)
Acetobacterium woody, ATCC 29683
(Acetobacterium Woodii, ATCC 29683)
Clostridium acetylicam, DSM 1496
(Clostridium aceticum, DSM 1496)
Clostridium glycolicum, ATCC29797
(Clostridium glycolicum, ATCC29797)
Clostridium SP No.307, FERM P-7487
(Clostridium sp No.307 FERM P-7487)
Clostridium SP No.484, FERM P-7488
(Clostridium sp No.484, FERM P-7488)
Clostridium SP No.68-2, FERM, P-7367
(Clostridium sp No.68-2 FERM, P-7367)
Clostridium SP No.670, FERM P-8047
(Clostridium sp No.670, FERM P-8047)
Clostridium SP No.672, FERM P-8049
(Clostridium sp No.672, FERM P-8049)
Eubacterium SP No.477, FERM P-8045
(Eubacterium sp No.477, FERM P-8045)
Eubacterium Rimosum, ATCC 8486
(Eubacterium limosum, ATCC 8486)
Eubacterium limosam, ATCC 10825
(Eubacterium limosum, ATCC10825)
Bacteroides SP No.669, FERM P-8046
(Bacteroides sp No.669, FERM P-8046)
Bacteroides SP No.671, FERM P-8048
(Bacteroides sp No.671, FERM P-8048)
Bacteroides ovatas, ATCC 8483
(Bacteroides ovatus, ATCC 8483)
Spolomucer Sphaeroides, DSM 2875
(Sporomusa sphaeroides, DSM 2875)
Sporomuza Ovata, DSM-2662
(Sporomusa ovata, DSM-2662)
Acetogenium kivi, ATCC 33488
(Acetogenium kivui, ATCC 33488)
Morella Thermosatica, ATCC 31490
(Moorella thermoacetica, ATCC 31490)
Morella Thermosatica, ATCC 35608
(Moorella thermoacetica, ATCC 35608)
Morella Thermosettica, ATCC 39073
(Moorella thermoacetica, ATCC 39073)
Morella Thermosettica, ATCC 39289
(Moorella thermoacetica, ATCC 39289)
Morella Thermosettica, ATCC 49707
(Moorella thermoacetica, ATCC 49707)
Morella Thermoautotropica, ATCC 33924
(Moorella thermoautotrophica, ATCC 33924)
The microorganism can be obtained from the depository indicated by the deposit number. Each deposit number indicates that the microorganism is deposited at the next depository.
FERM Patent Organism Depositary; International Patent Organism Depositary (IPOD)
http://unit.aist.go.jp/pod/ci/index.html
ATCC American Type Culture Collection (ATCC)
http://www.atcc.org/
DSM German Collection of Microorganisms and Cell Cultures (DSMZ)
http://www.dsmz.de/

  The above microorganisms often produce alcohol such as ethanol together with acetic acid. A method of adjusting the ratio of each product to produce one more preferentially is known. For example, an acetic acid producing bacterium has a pathway for producing acetic acid from acetyl CoA in an acetic acid producing metabolic pathway. Methods for forcing the metabolic pathway to ethanol production by inhibiting acetic acid production are also known.

<Medium contained in fermentation broth>
In the present invention, anaerobic microorganisms capable of immobilizing gaseous resources as organic substances are brought into contact with hydrogen and carbon monoxide and / or carbon dioxide under conditions suitable for the production. The condition suitable for production in the present invention means that, for example, when acetic acid is produced, the survival and activity of anaerobic microorganisms having acetic acid producing activity are maintained. More specifically, it means that anaerobic conditions that allow anaerobic microorganisms to survive are maintained, and nutrients are provided to support the activity and growth of the microorganisms. Various medium compositions suitable for the survival of anaerobic microorganisms are known. Therefore, those skilled in the art can select an appropriate medium composition even for the anaerobic microorganisms having the ability to produce acetic acid described above.

For example, a water-soluble organic substance can be added as a carbon source to the medium used in the present invention. The following compounds can be listed as water-soluble organic substances.
Sorbose fructose glucose The concentration of organic substances added to the medium as a carbon source can be appropriately adjusted in order to efficiently grow microorganisms in the medium. Generally, excess and deficiency can be avoided by selecting the addition amount from the range of 0.1 to 10 wt / vol%.

In addition to the above carbon source, a nitrogen source is added to the medium. In the present invention, various nitrogen compounds that can be used for normal fermentation can be used as the nitrogen source. Preferred nitrogen sources are ammonium salts and nitrates. More preferable nitrogen sources are ammonium chloride and sodium nitrate, but it is also possible to supply gaseous resources as ammonia gas to the culture solution via a gas supply device. Furthermore, in addition to the carbon source and nitrogen source, other organic substances or inorganic substances suitable for culturing microorganisms can be added to the medium. For example, in some cases, the growth or activity of microorganisms can be enhanced by adding inorganic compounds such as cofactors such as vitamins and various salts to the medium. For example, the following can be mentioned as microbial growth cofactors derived from inorganic compounds, vitamins and animals and plants.
Inorganic compounds Vitamins Potassium dihydrogen phosphate Biotin Magnesium nitrate Folic acid Manganese nitrate Pyridoxine Sodium chloride Thiamine Cobalt Riboflavin Calcium chloride Nicotinic acid Zinc sulfate Pantothenic acid Copper sulfate Vitamin B12
Alum thioctic acid sodium molybdate p-aminobenzoic acid boric acid etc. microbial growth co-factor derived from animals and plants yeast extract meat extract peptones

  Methods for producing a culture solution by adding these inorganic compounds, vitamins, or growth cofactors are known. The medium can be liquid, semi-solid, or solid. In the method for producing acetic acid of the present invention, the preferred medium form is preferably an aqueous solution as the liquid medium. In the present invention, the anaerobic microorganism can be cultured according to a known anaerobic microorganism culture method. For industrial production, a continuous fermentation system that can continuously supply a medium and a substrate gas and has a mechanism for collecting a culture is suitable. A particularly preferred system is specifically illustrated in the embodiments.

<Fermenter>
In the culture of anaerobic microorganisms, it is necessary to prevent oxygen from being mixed into the continuous culture system. As the incubator, a commonly used culture tank can be used as it is. Culture tanks that can also be used for culturing anaerobic microorganisms are commercially available. Anaerobic atmosphere can be created by replacing oxygen mixed in the culture tank with an inert gas such as nitrogen or substrate gas before inoculation in advance. It is sufficient to feed the fermented liquor in which the cells have been cultured separately to the fermentor after sufficiently performing the empty operation of filling the gas and moving the gas supply device.

The fermenter can be, for example, an anaerobic jar used as a bioreactor for the culture of anaerobic microorganisms. The anaerobic culture jar may be any one that is composed of an airtight container made of metal, glass, or synthetic resin and that can shield the inside from oxygen in the atmosphere. In particular, keeping the fermenter internal pressure slightly higher than the atmospheric pressure is preferably performed to prevent contamination of the fermentation system from the outside. It is also possible to make the gas phase side of the gas supply device function as a fermenter and omit the fermenter.
In addition, sensors such as a pressure gauge, thermometer, pH meter, COD meter, oxygen concentration meter, conductivity meter, infrared spectrophotometer, etc. are attached to the liquid phase part and the gas phase part of the fermenter. It is very preferable to monitor the environment of the fermentation broth based on the information obtained (monitoring).

Depending on the shape of the fermenter, it is preferable to stir sufficiently to eliminate unevenness of the culture solution, and a commercially available stirrer or the like can also be used. By stirring the culture in the culture tank, it is possible to increase the chance that the medium components and gas resources are brought into contact with the anaerobic microorganisms, and to optimize the production efficiency of the organic matter.
For sufficient growth of microorganisms, the hydrogen ion concentration of the culture is preferably 4.0 to 8.0, more preferably 4.5 to 7.5. Moreover, in order to increase production of organic matter, the temperature of the culture tank is preferably 25 ° C to 55 ° C, more preferably 30 ° C to 50 ° C. In the continuous culture system, a fresh medium is continuously or intermittently supplied to the fermenter. In order to efficiently produce organic substances, the amount of fresh medium supplied to the fermenter is preferably 0.04 to 2 / hr per hour in the culture in the culture tank. A more preferable dilution rate is 0.08 to 1 / hr. Moreover, it can replace with a fresh culture medium and the culture solution containing the fresh microbial cell cultured separately by batch can also be used.
Furthermore, in order to adjust the amount of liquid in the fermenter, or to remove aging bacterial cells and trace accumulation components, the fermented liquid returned continuously or intermittently directly from the fermentor, or from the gas supply device or filtration device Can also be disposed of outside the system. Alternatively, continuously or intermittently discharging the gas phase accumulated in the upper part of the fermenter to the outside of the system is an important operation for maintaining the pressure in the apparatus properly and for removing unnecessary gas components that accumulate. is there.

<How to take out the product>
The organic matter produced in the fermenter can be taken out from the fermented liquid by a known means by directly taking out the fermented liquid sent or returned from the fermenter or to the gas supply device or the filtration device. For example, solvent extraction method, distillation method, adsorption method, dialysis method, electrodialysis method, membrane separation method, etc. can be raised, but since the treatment is easy and the effect on the bacterial cells is small, the filtrate of fermentation broth should be used. It is preferable to take out the organic matter before supplying it to the gas supply device.

  For example, the filtrate of the fermentation broth: 102b is fed to the extraction device: 107, and the produced organic acid or alcohol is brought into contact with the organic solvent to extract from the aqueous phase to the organic phase, and then the filtrate after the extraction treatment By sending: 102d to the gas supply device: 104, generation of a gas that becomes a problem in solvent extraction can be suppressed as much as possible. The organic solvent after extraction can be separated and recovered from the organic solvent produced by the microorganisms from the organic solvent by a known method such as neutralization, distillation, and back extraction alone or in combination in the valuable material separation device 108. it can.

  The organic solvent is preferably a hydrocarbon compound having low solubility in water and low toxicity to cells, and an aliphatic hydrocarbon having a solubility in water of 0.05 g / 100 g (25 ° C.) is particularly preferably used. When the organic substance produced is an organic substance such as acetic acid, the extraction efficiency can be further increased by appropriately dissolving the organic compound that selectively binds to the organic acid in an organic solvent. Monoethanolamine (MEA) Diethanolamine (DEA) , Organic amines such as diglycolamine (DGA) and phosphorus compounds such as tributyl phosphate (TBP) and tri-n-octyl phosphine oxide (TOPO) are used.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component and description is abbreviate | omitted suitably.

<Organic production apparatus of the present invention>
The present invention comprises anaerobic culture in an aqueous medium containing (1) H ₂ and (2) one of or both of CO ₂ and CO to produce organic matter, comprising the following components: The present invention relates to an apparatus for producing an organic substance for producing an organic substance in the aqueous medium.
(1) A gas permeable membrane that allows permeation of the gas to a gas phase containing at least one gas of H ₂ , CO ₂ , and CO, wherein the aqueous medium is passed through the gas permeable membrane and the other A gas permeable membrane that forms an interface where gas exchange takes place between the two when the gas phase is disposed in
(2) a gas circuit connected to the gas permeable membrane of (1) and circulating a gas constituting a gas phase containing at least one gas of H ₂ , CO ₂ , and CO; and
(3) An aqueous medium circuit that is connected to the gas permeable membrane of (1) and circulates the aqueous medium.

The basic structure of the organic substance manufacturing apparatus of the present invention will be described with reference to FIG. The organic substance production apparatus of the present invention is (1) a gas permeable membrane that allows gas to pass through a gas phase containing at least one gas of H ₂ , CO ₂ , and CO, the gas permeable membrane being And a gas permeable membrane that forms an interface where gas exchange is performed between them when an aqueous medium is disposed on one side and a gas phase is disposed on the other side. A preferred gas permeable membrane is a microporous membrane made of a hydrophobic material. The gas permeable membrane exchanges gas at the interface between the gas phase and the liquid phase, and acts as a gas supply device for supplying gas resources to the aqueous medium constituting the liquid phase. The gas supply device shown in FIG. 1 supplies gas resources such as hydrogen, carbon dioxide, or carbon monoxide supplied to the gas phase side to the liquid phase via a gas permeable membrane (broken line). On the other hand, an aqueous medium (fermented liquid) is supplied from the fermenter to the gas supply device, and a gas-liquid interface is formed through a gas permeable membrane in the gas supply device, and gas exchange is performed at the gas-liquid interface. The gas supply device can be constituted by a gas exchange module constituted by, for example, a gas exchange membrane. As described above, the gas exchange module is a bundle of hollow fibers made of a gas permeable membrane and packed in a column. The column is made of stainless steel or plastic, and includes a connection valve that supplies an aqueous medium to the outside of the hollow fiber packed inside the column. The gas exchange module is also provided with a connection valve for supplying a gas phase to the hollow fiber lumen filled in the module. Gas exchange can be performed by circulating a gas phase in, for example, the lumen of the hollow fiber and circulating an aqueous medium (fermented liquid) outside. Alternatively, the gas exchange module can be simply filled with the fermentation liquor, and the inside of the gas supply device can be used as a fermenter.

The organic substance manufacturing apparatus of FIG. 1 includes a gas circuit that is connected to a gas permeable membrane in a gas resource supply apparatus and circulates a gas constituting a gas phase containing at least one gas of H ₂ , CO ₂ , and CO. In the gas circuit, the gas constituting the gas phase circulates in the closed circuit. The gas circuit is airtightly connected to a gas phase supply connection valve connected to the inside of the hollow fiber of the gas resource supply device, and includes a pump for circulating the gas phase therein. The most basic gas circuit is composed of a pipe made of metal, synthetic resin, glass or the like connected to a gas supply device. The gas circuit may be provided with a valve for adjusting the supply amount of the gas resource. In the gas circuit, any treatment such as deoxygenation treatment can be performed as described above. Further, the gas can be discarded from the gas circuit, or conversely, a new gas can be replenished to the gas circuit.

  1 includes an aqueous medium circuit that is connected to a gas permeable membrane and circulates an aqueous medium. In FIG. 1, the aqueous medium circuit supplies a part of the fermented liquid in the fermenter to the gas supply device for gas exchange, and then returns the fermented liquid to the fermenter. The fermenter is a liquid-tight container made of synthetic resin or stainless steel and is provided with a temperature adjustment mechanism as necessary. The fermented liquid in the fermenter is supplied to the gas resource supply device as an aqueous medium. The aqueous medium circuit that transfers the aqueous medium has a liquid-tight structure that connects the gas resource supply device and the fermenter. Specifically, a tubular structure of metal or synthetic resin can be connected to a connection valve connected to the outside of the hollow fiber of the gas exchange module to form an aqueous medium circuit. The aqueous medium circuit can include a filter membrane for filtering anaerobic microorganisms in addition to a pump for circulating the aqueous medium. On the other hand, in the fermenter, various sensors such as an in-line spectrophotometer, an edometer, a dissolved oxygen sensor (DO electrode), and a pH electrode can be arranged to monitor the environment of the fermentation broth. Furthermore, a valve for discarding the gas staying in the fermenter can be provided. Subsequently, preferred embodiments of the apparatus of the present invention will be specifically described below.

<First organic matter production equipment: 100>
FIG. These are the process flows which show an example of a structure of the organic substance production apparatus by the microorganisms of this embodiment. Organic substance production apparatus: 100 is an apparatus for producing gas resources (carbon monoxide and / or carbon dioxide and hydrogen): 101 from organic substances: 116, for example, organic substances: 116, organic acids such as acetic acid and / or alcohol such as ethanol, etc. It is. However, pressure gauges, thermometers and other instruments, safety valves, drain valves, heating equipment, cooling equipment, heat insulating materials, observation windows, sample inlets, sampling ports, and other normal valves and valves, piping, hatches, etc. The equipment and parts that the apparatus should have and the instruments and parts necessary for operation management of the apparatus can be appropriately provided and used unless otherwise specified, and are omitted from the following description.

  The organic matter production apparatus: 100 (FIG. 3) includes a gas supply apparatus: 104. The gas supply device: 104 is partitioned into a gas phase part: 104b and a liquid phase part: 104c via a hydrophobic gas permeable membrane: 104a, and the shape is not limited. For example, when the hydrophobic gas permeable membrane 104a is a hollow fiber membrane, the inside and the outside partitioned by the hollow fiber membrane are applicable. Normally, the outside of the hollow fiber membrane and the outer cylinder (shell or housing) containing the bundle of hollow fiber membranes are used as the liquid phase, and the inside of the hollow fiber membrane is used as the gas phase. It does n’t matter. In addition, the liquid phase part: 104c and the fermented liquid circulation pipe also serve as a so-called fermenter.

  The liquid phase part: 104c is filled with a fermentation liquid: 102 consisting of an aqueous solution of microorganisms and a medium, and the liquid phase part: 104b is connected to both ends of the fermented liquid and connected to the outlet, and a gas supply device: 104 The fermentation liquid 102 flows along the gas permeable membrane 104a. Fermentation liquid: 102 is sent from the fermented liquid-containing pipe to the liquid phase part: 104b of the gas supply device: 104 by the fermentation liquid supply pump: 109a. Further, from the fermentation liquid outlet pipe at the other end, the fermentation liquid subjected to absorption and removal of the gas phase part 104b and gas components is taken out from the gas supply device 104 through the hydrophobic gas permeable membrane 104a. Fermentation fluid circulation valve: Fermentation fluid circulation piping equipped with 110a connects the fermentation fluid into and out of the piping, but the connection of the circulation piping to the fermentation fluid piping is on the inlet side of the fermentation fluid supply pump: 109a Is provided. In addition, the fermented solution inlet and outlet pipes are respectively provided with a fermented solution containing valve 110b and a fermented solution outlet valve 110c outside the circulation pipe.

  When supplying 102d of fermentation broth such as culture medium, water, and new microorganisms to the fermentation broth, open the fermented liquid valve: 110b and the fermented liquid discharge valve: 110c and replenish the feed liquid while fermenting a part of the fermented liquid. Take it out of the system from the drain pipe. In order to keep the pressure of the liquid phase part: 104b appropriately, the opening degree of the fermented liquid containing valve: 110b and the fermented liquid outlet valve: 110c can be appropriately adjusted. Moreover, when performing this operation, the fermented liquid circulation valve: 110a is normally closed, but can also be performed while circulating a part of the fermented liquid at an appropriate opening degree. In addition, it is possible to perform only one of the supply liquid supply and the fermentation liquid removal, but the pressure of the liquid phase part 104b must be kept appropriately.

  On the other hand, the gas phase portion: 104b is filled with a gas resource: 101 containing at least carbon monoxide and / or carbon dioxide and hydrogen. The gas phase part: 104b is connected to the gas entry, exit and circulation pipes at both ends. The gas supply device: 104 is housed inside the gas permeable membrane: 104a, and the gas resource: 101 flows along the structure. Have. Hydrophobic gas permeable membrane: 104a and liquid phase part: 104c and gas components supplied and absorbed gas are exhausted from gas supply device: 104 by gas circulation pump: 109b provided in gas outlet pipe From the other end of the gas phase part: 104b provided in the gas supply device: 104 by the circulation pipe, the gas is returned to the gas phase part: 104b. As a result, the gas in the gas phase part: 104b is circulated inside the gas supply unit: 104, and is repeatedly brought into contact with the liquid phase part: 104c to efficiently supply and absorb the gas component.

The gas-filled pipe is equipped with a gas supply valve: 110d, which is normally closed, but is opened at an appropriate opening to adjust the pressure in the gas phase section: 104b and replenish gas resources consumed by microorganisms. The gas resource: 101 is supplied to the gas supply device: 104 by being left standing or being opened intermittently. The pressure of the gas resource: 101 is set higher than the gas phase part: 104b, and the pressure of each component of the gas phase part: 104b is the present invention relative to the pressure of each gas component contained in the liquid phase part: 104c. In addition, the composition of each component of the gas resource: 101 needs to be a composition that maintains the gas-liquid interface pressure difference of the present invention.
However, as long as this condition can be maintained, the gas circulation pipe can be connected to the gas supply device 104 side from the gas supply valve 110d of the gas-containing pipe.

The gas circulation pipe provided with the gas disposal valve: 110e is connected to the gas circulation pipe that sends the gas from the gas outlet pipe to the outside of the gas supply device 104 by the gas circulation pump 109b. Gas disposal valve: 110e is normally closed, but the gas phase part: 104b is properly opened to discharge unnecessary gas components accumulated in the gas phase part: 104b and to properly adjust the pressure of the gas phase part: 104b. It is discharged as waste gas resource: 101b from the gas supply device: 104 by keeping it open at all times or opening it intermittently.
The flow direction of the gas and liquid in the gas supply unit: 104 inside the gas phase part: 104b and the liquid phase part: 104c is not particularly limited, but in order to perform gas-liquid contact more efficiently It is desirable to become a flow.

<Second organic matter production equipment: 200>
FIG. These are the process flows which show another example of the structure of the organic substance production apparatus by the microorganisms of this embodiment. The organic matter production apparatus: 200 basically has the same configuration as the organic matter production apparatus: 100. Therefore, the following description will focus on the points specific to the organic matter production apparatus 200.

  The organic matter production apparatus 200 includes a gas supply device 104 and its associated pipes, valves, and pumps in the same manner as the organic matter production apparatus 100, and a gas circulation pipe and a gas phase buffer tank 105. In either case, the installation position is not particularly limited, but it is preferable to install the gas disposal pipe connecting part and the gas supply device: 104 return part for easy operation management. Further, a circulating gas adjustment valve: 110f may be provided on the gas phase buffer tank: 105 outlet side. Furthermore, the gas supply pipe provided with the gas supply valve: 110d can be connected to the entry side or the exit side of the gas phase buffer tank: 105 instead of the gas supply device: 104. When connected to the inlet side of the gas phase buffer tank: 105, it is preferable to connect to the circulation pipe connection side of the gas supply device: 104 from the connection part of the waste gas pipe, the gas phase buffer tank: 105, gas resource: 101 And the gas resource after processing the gas supply device: 101a can be efficiently mixed and supplied to the gas supply device: 104. Since the waste gas resource: 101b is discarded, the gas resource: 101 is effectively used. And its gas circulation path.

Alternatively, the hydrogen recovery device 111 described in the organic matter production device 600 can be installed in series or in parallel with the gas phase buffer tank 105. The gas rich in hydrogen separated by the hydrogen recovery device 111 is sent to the gas supply device 104 and used as a circulating gas, and the gas poor in hydrogen is preferably discarded as it is outside the system.
Gas phase buffer tank: Keeping oxygen scavenger: 112 inside the gas buffer tank: 105, gas resource after processing gas supply device: oxygen contained in 101a, gas disposal valve: open 110e, gas resource out of the system : 101 is particularly preferably carried out in order to keep the oxygen partial pressure in the gas phase portion 104b of the gas supply device low without unnecessary disposal. Furthermore, connecting the gas supply pipe provided with the gas supply valve: 110d to the entrance side of the gas phase buffer tank: 105 instead of the gas supply device: 104 removes the oxygen contained in the gas resource: 101 in advance. Gas supply device: One of the most desirable modes since it can be supplied to 104.

  The supply and replacement of the oxygen scavenger: 112 can be easily performed by appropriately attaching a dedicated pipe or the like to the gas phase buffer tank: 105. In addition, by connecting a plurality of gas phase buffer tanks: 105 to the circulating gas pipes in parallel and switching them, the deoxidant: 112, which has been consumed, can be replaced or regenerated. This can be done easily while driving.

<Third organic matter production equipment: 300>
FIG. These are the process flows which show another example of the structure of the organic substance production apparatus by the microorganisms of this embodiment. The organic matter production apparatus: 300 basically has the same configuration as the organic matter production apparatus: 200. Therefore, the following description will focus on the points specific to the organic matter production apparatus 300.
The organic substance production apparatus: 300 is equipped with the gas supply apparatus: 104 and the gas phase buffer tank: 105 and its associated pipes, valves, and pumps as well as the organic substance production apparatus: 200, and the fermenter: 103 with the gas supply apparatus: 104. Provided on the fermented solution piping side.
The fermenter: 103 is connected to the fermented liquor entry / extraction pipe in the organic matter production apparatus: 200 and communicated with the gas supply apparatus: 104. The fermenter: 103 plays a role of strengthening and improving the efficiency of the microbial fermenter function which the liquid phase part: 104c of the gas supply device and the fermenter circulation pipe fulfilled in the organic matter production apparatuses: 100 and 200. Fermenter: 103 has a volume corresponding to the gas resource supply function of gas supply device: 104, and microorganisms assimilate and produce gas resources as organic matter in the fermentation liquid (consisting of microorganisms, medium, water, etc.) In order to provide sufficient residence time and environment.

<Fermentor: 103>
As the fermenter: 103, any known type of fermenter can be used. Then, a common jar-type fermenter is illustrated and one structure is illustrated. The fermenter: 103 includes a stirrer: 113. FIG. In the above, a stirrer having a paddle type stirring blade is exemplified, but various stirrers can be selected as appropriate. A stirrer: 113 is used depending on the volume and shape of the fermenter: 103, and the position and shape of the fermentation liquor entry and extraction pipes. You can not. The stirrer: 113 is sufficient to rotate the stirring blades at a very low speed so that the concentration and sedimentation of the fermented liquid can be prevented and the composition and temperature of the fermented liquid in the fermenter can be kept uniform.

  Moreover, the fermenter: 103 is provided with various sensors: 114. Various sensors: 114 can be exemplified by pressure gauge, thermometer, pH meter, COD meter, oxygen concentration meter, conductivity meter, infrared spectrophotometer, etc. Fermenter: 103 liquid phase if necessary Part: 103a and / or gas phase part: 103b. The information obtained from various sensors is combined with the operation information obtained from other equipment of the organic matter production device: 300, and is most appropriate for microorganisms to assimilate and produce gaseous resources as organic matter in the fermented liquid: 102. For the purpose of maintaining the environment, it is used to adjust the operating state of each device constituting the organic matter production apparatus 300.

To the liquid phase part: 103a and the gas phase part: 103b of the fermenter: 103, pipes respectively having a fermentation liquid adjustment valve: 110f and a gas disposal valve: 110g can be connected. Although both valves are normally closed, the liquid phase: 103a fermentation liquid and the gas phase: 103b gas can be taken out of the apparatus and discarded by opening as necessary.
Liquid phase part: The amount of liquid can be adjusted by discarding the fermentation liquid of 103a. If replenishment and disposal of the fermentation broth are performed at the same time, a part of the fermentation broth can be replaced with a fresh supply liquid, and old cells and accumulated unnecessary components can be removed from the fermentation broth: 102. In addition, instead of the fermented liquid adjustment valve: 110f, a pipe provided with the fermented liquid take-out valve: 110h can be connected to the fermented liquid-containing pipe or the outgoing pipe connected to the gas supply device 104. Further, the fermented liquor: 102 held in the fermenter: 103 is taken out from these pipes, and instead of discarding it, it can be used as a production liquid for the organic matter producing apparatus: 300 for a process of separating and collecting the target organic matter. it can.
It is preferable to keep the pressure of the gas phase part: 103b slightly higher than the atmospheric pressure at all times in order to maintain the anaerobic condition of the fermenter: 103 and prevent contamination by other cells. However, if the gas disposal valve: 110g is partially or intermittently opened as necessary, a part of the gas in the gas phase part: 103b is taken out of the apparatus and discarded. This operation is necessary for removing unnecessary components that accumulate. Performing in conjunction with the operation of supplying the feed liquid: 102d to the fermentor: 103, which increases the liquid volume, does not decrease the pressure of the gas phase part: 103b, for example, 100 Pa or more, preferably 1000 Pa or more higher than the outside Thus, a part of the gas phase part: 103b can be taken out, which is preferable.

The fermenter: 103 is connected to the fermented liquor entry / extraction pipe in the organic matter production apparatus: 200 and communicated with the gas supply apparatus: 104. The fermented liquor is fed from the liquid phase part of the fermentor: 103a to the gas supply device: 104 by the fermented liquid supply pump: 109a installed in the immediate vicinity of the fermenter: 103, and the fermented liquid take-out pipe of the gas supply device: 104 Thus, the fermented liquid after the gas supply device treatment: 102a is returned to the fermenter: 103. When connecting a pipe equipped with a fermented liquid take-off valve: 110h to this fermented liquid-containing pipe, connect it to the outlet side of the fermented liquid supply pump: 109a and adjust the amount of liquid fed to the gas supply device: 104 It is preferable to take out the fermented liquor: 102 because the apparatus can be easily managed.
In addition, a pipe equipped with a fermented liquid valve: 110b may be connected to the fermented liquid take-out pipe in the immediate vicinity of the fermenter: 103, but a pipe equipped with the fermented liquid valve: 110b is connected to the fermenter: 103. Direct supply can easily supply the supply liquid: 102d. However, in any case, the pressure of the supply liquid: 102d needs to be kept higher than the supply side.

  In addition, FIG. However, the fermenter: 103 has a temperature control function, and maintains the most suitable environment for the microorganisms to assimilate and produce gaseous resources as organic substances in the fermented liquid: 102. The temperature control function can be appropriately selected from known methods. For example, there is a method in which the fermenter: 103 is covered with a jacket, or a serpentine tube through which the temperature control liquid flows is provided in the fermenter: 103. Moreover, the temperature of each apparatus which comprises the organic substance production apparatus: 300 can also be adjusted by heat-maintaining the apparatus and piping of the organic substance production apparatus: 300, or using a double pipe.

<Fourth organic matter production equipment: 400>
FIG. These are the process flows which show another example of the structure of the organic substance production apparatus by the microorganisms of this embodiment. The organic matter production apparatus: 400 has basically the same configuration as the organic matter production apparatus: 300. Therefore, the following description will focus on the points unique to the organic matter production apparatus 400.

Organic matter production equipment: 400, gas supply equipment: 104, gas phase buffer tank: 105, fermenter: 103 and its attached piping, valves, and pumps are provided in the same manner as organic matter production equipment: 300, and filtration device: 106 is fermented The tank: 103 and the gas supply device: 104 are provided on the side of the fermentation solution-containing piping. The filtration device 106 is connected to the fermenter take-out pipe and the fermenter return pipe of the fermenter 103, communicated with the fermenter 103, and the fermenter feed pump installed in the immediate vicinity of the fermenter 103: 109a The fermented liquid: 102 is supplied from the liquid phase part of the fermenter: 103a to the raw liquid inlet of the filtration device: 106, the concentrated liquid: 102c is taken out from the concentrated liquid outlet side, and the concentrated liquid is returned with the concentrated liquid valve: 101i. Returned to fermenter: 103 by piping. The filtration device 106 can be appropriately selected from known filtration devices, and the operation thereof is also performed by a known method.
Further, the filtrate outlet 106 (permeate outlet) of the filtration device 106 is connected to a pipe having the fermented liquid valve 110b in the organic substance production device 300 of the gas supply device 104, and the filtrate supply pump 109c. Is fed to the gas supply device 104. The fermented liquor: 102a after the gas supply device treatment is returned to the fermenter: 103 directly from the gas supply device: 104 and the fermentor: 103 or from the fermentation liquor return pipe connected to the concentrate return pipe.

The filtrate discharged from the fermented liquid supply pump: 109a installed in the immediate vicinity of the fermenter: 103 is sent to the gas supply device: 104 through the filtrate supply pipe. Filtrate extraction valve with 110j in the middle of the liquid supply path to the gas supply unit: Connect the filtrate extraction line with 110j to the filtrate supply line. Can be taken out of the system. As described in the example of the configuration of the organic matter production apparatus: 100, 200, 300, 400, the place where the organic material production apparatus: 400 takes out the organic substance assimilated and produced by the gas resources can be selected as appropriate. The state of the fermented liquor for collecting the organic matter varies depending on the place to be taken out. Specifically, the following fermentation broth can be taken out from the organic matter production apparatus: 400 for organic matter recovery.
Fermentation liquid containing target organic matter and bacterial cells: 102
Fermented liquid after gas supply device treatment: 102a (with or without filtration)
Filtrated filtrate: 102b or concentrate: 102c
Regardless of which fermented liquor is taken out, the organic substance recovery method is known. Gas supply device: When taken out as filtrate: 102b before being supplied to 104, the concentration of low-molecular organic substances is the highest, and since it does not contain solids such as bacterial cells, it contains the least amount of gas resources. It is most preferable because the organic substance can be easily separated and recovered. Filtrate: 102b can be taken out continuously by adjusting the opening of the filtrate take-off valve: 110j or intermittently, but in conjunction with the supply of the supply liquid: 102d It is preferable from the stable operation management of the organic matter production apparatus: 400.

<Fifth organic matter production equipment: 500>
FIG. These are the process flows which show another example of the structure of the organic substance production apparatus by the microorganisms of this embodiment. The organic matter production apparatus: 500 basically has the same configuration as the organic matter production apparatus: 400. Therefore, the following description will focus on the points peculiar to the organic matter production apparatus 500.

Organic matter production device: 500 is equipped with gas supply device: 104, gas phase buffer tank: 105, filtration device: 106 and fermenter: 103 and its attached piping, valves and pumps as well as organic matter production device: 400, extraction Device: 107 and organic substance separation device: 108 are provided. The extraction device 107 is installed between the filtration device 106 and the gas supply device 104 between the fermentation solution-containing piping. Further, the organic substance separation device 116 is connected to an extraction liquid supply pipe including an extract liquid supply pump 109e.
The fermenter: 103 and the gas phase buffer tank: 105 and their attached pipes, valves and pumps are basically the same as those of the organic matter production apparatus: 400, FIG. Is not explicitly stated. Further, like the organic substance production apparatus 400, the gas phase buffer tank 105 can be omitted.

Extraction device: 107 is connected to and connected to the filtrate inlet of the filtration device: 106, the filtrate extraction pipe of the gas supply device: 104. The filtrate: 102b is fed from the filtration device: 106 to the filtrate inlet of the gas supply device: 104.
Further, the filtrate 102d after the extraction treatment from the extraction device 114 is sent to the fermentation solution-containing pipe side of the gas supply device 104 by the extraction residual liquid supply pump 109d. Usually, an organic solvent having a specific gravity lower than that of the filtrate (aqueous solution) is used for the extract: 117, so that the filtrate: 102d is supplied from the upper part near the center of the extractor: 115 and collected at the lower part of the extractor: 115. The filtrate 102d after the extraction treatment is extracted from the lower part of the extraction device 115.
On the other hand, the extract liquid 115 is supplied from the lower part near the center of the extractor 107, and the extract liquid 115 after extraction collected at the upper part of the extractor 115 is extracted from the upper part of the extractor 107. In addition, a well-known extraction apparatus can be selected suitably for an extraction process, and the piping and operation in that case are performed by the means most suitable for the selected apparatus.
The organic matter production apparatus: 500 shown in the figure is separated and recovered from the fermented liquor: 102 by the extraction method of the organic matter: 116 produced by fixing and assimilating the gas resource: 101 by microorganisms in the organic matter production apparatus: 400. One embodiment has been illustrated. When the organic material produced by fixing and assimilating the gas resource: 101 by microorganisms is separated by another means, an apparatus for performing another means can be installed instead of the extraction device: 107.

  Extracted extraction liquid 115 extracted from the upper part of the extraction apparatus 107 is sent to the organic matter separation apparatus 108 by an extraction liquid feeding pump equipped with an extraction liquid feeding pump 109e. In the organic matter separation device 108, the organic matter produced by fixing and assimilating the gas resource 101 by microorganisms is recovered from the extract, and the extract is regenerated. The regenerated extract: 115 is returned to the extractor: 107 and recycled. In the organic matter separation device: 108, both are separated by a known method in accordance with the characteristics of the used extract: 115 and the produced organic matter: 116, and the produced organic matter: 116 is recovered. Note that the organic substance separation device 108 may be composed of a plurality of steps by a known separation method.

<Sixth organic matter production equipment: 600>
Organic matter production device: 600 (Fig. 8) is equipped with gas supply device: 104 and its associated piping, valves, and pumps as well as organic matter production device: 100, and organic matter production device: 200 gas phase buffer in the gas circulation pipe Tank: In place of 105, hydrogen recovery 111 is provided. Although there is no restriction | limiting in particular in an installation position, It is preferable to install in the gas waste piping connection part and gas supply apparatus: 104 return part with easy operation management.
Furthermore, the gas supply pipe provided with the gas supply valve: 110d can be connected to the entry side or the exit side of the hydrogen separation device: 111 instead of the gas supply device: 104. Hydrogen recovery device: When connected to the inlet side of 111, it is preferable to connect to the circulation piping connection side of the gas supply device: 104 from the connection part of the waste gas piping, and the gas resource: 101 and the gas resource after processing the gas supply device : From the gas mixture of 101a, the hydrogen recovery device: 111 can be supplied to the gas supply device: 104 as a gas resource rich in hydrogen processed by 111: Waste gas resource: 101d instead of 101b It can be discharged out of the system. In particular, when the hydrogen recovery device 111 is a “molecular sieve” membrane and a separation membrane that selectively permeates low-molecular hydrogen, excess carbon dioxide, inert gas such as nitrogen, hydrogen sulfide or sulfur oxide, or nitrogen Since an impurity gas such as an oxide is preferentially contained in the gas resource 101d that is poor in hydrogen, the waste gas resource 101b can be eliminated. Further, by opening / closing or adjusting the opening degree of the gas discard valve: 101m poor in hydrogen, the gas 101d poor in hydrogen: 101d can be discharged out of the system intermittently or continuously.

The vapor phase buffer tank 105 described in the organic substance production apparatus 200 can be provided together with the hydrogen separation apparatus 111. In this case, a plurality of hydrogen separators 111 and gas phase buffer tanks 105 can be installed in series or in parallel. In the hydrogen separator 111, the gas resource rich in hydrogen: 101c becomes deficient in carbon monoxide and / or carbon dioxide, so the opening of the circulating gas bypass valve: 110n is adjusted, and the gas supply device: 104 It is necessary to adjust the composition of the circulating gas supplied to the tank.
Further, when the deoxidizing agent: 112 is placed in the gas phase buffer tank: 105 to perform the deoxygenation treatment, it is preferable to install the gas phase buffer tank: 105 in the subsequent stage of the hydrogen separator: 111. This is because when the “molecular sieve” membrane is used, the hydrogen recovery device: 111 itself has a certain degree of oxygen removal function, so that the oxygen scavenger: 112 can be used effectively.
Hereinafter, the present invention will be described in more detail with reference to examples.

  The organic substance production apparatus used is shown in FIG. 500 mL of the culture solution having the composition shown in Table 1 was dispensed and sterilized in a 1 L fermentor, and DO of the culture solution was measured. The DO was 40%. Next, a mixed gas of hydrogen and carbon dioxide (4: 1) is supplied to a gas supply device equipped with Liqui-Cell (registered trademark), 1 × 5.5 ″ (Celgard), supply pressure 0.1 MPa, flow rate 1.0 L / Circulated and supplied at min. At the same time, the culture solution was circulated and supplied at 25 mL / min between the fermenter and the gas supply device. The fermenter was stirred at 250 rpm. The DO of the culture solution after 30 minutes was 0%, and the remaining air could be removed. Next, the culture solution was inoculated with Acetobacterium Woodii (ATCC 29683), and cultured at 35 ° C. under the same operating conditions of the organic matter production apparatus as before the inoculation. When the inoculated cell concentration was 2.7 g dry cell / L, acetic acid 4 g / L was accumulated after 5 hours.

[Comparative Example 1]
The same organic substance production apparatus as in Example 1 was used, and acetic acid production was examined under the same conditions as in Example 1 except that the mixed gas supply pressure of hydrogen and carbon dioxide (4: 1) was not applied to the gas supply apparatus. The DO after 30 minutes of operation of the organic matter production apparatus was 10%. Next, bacteria were inoculated and cultured at 35 ° C. in the same manner as in Example 1, but acetic acid was not produced.

[Comparative Example 2]
Using an organic matter production apparatus (FIG. 2) without a gas supply device, dispensing and sterilizing the culture broth as in Example 1 and mixing a mixed gas of hydrogen and carbon dioxide (4: 1) to the fermenter It was circulated. The DO of the culture broth after 50 minutes of operation was zero. As in Example 1, Acetobacterium Woodii (ATCC 29683) was inoculated and cultured at 35 ° C. When the inoculated cell concentration was 2.7 g dry cell / L, acetic acid was obtained after 5 hours. Accumulated 1.2 g / L.

The organic production apparatus used is shown in FIG. 200 mL of the culture solution having the composition shown in Table 1 was sterilized in advance and supplied to the fermenter part of the fermenter equipped with a gas supply device equipped with Liqui-Cell (registered trademark), 1 × 5.5 ″ (Celgard). Next, a mixed gas of hydrogen and carbon dioxide (4: 1) was circulated to the gas supply device at a supply pressure of 0.1 MPa and a flow rate of 1.0 L / min. At the same time, the culture solution was circulated and supplied at 25 mL / min. After 30 minutes, Acetobacterium Woodii (ATCC 29683) was inoculated into the culture solution in the fermenter part, and cultured at 35 ° C. under the same apparatus operating conditions as before the inoculation. When the inoculated cell concentration was 1.4 g dry cell / L, acetic acid 2.6 g / L was accumulated after 6 hours.
hydrogen. Carbon dioxide and each gas were measured by a gas chromatograph using TCD detection, and acetic acid was detected by a high-speed liquid kumatograph by UV.

[Table 1]
Composition of culture solution (in 1L)
0.1% resazurin aqueous solution 1mL
10% NH ₄ Cl aqueous solution 10 mL
1M KH ₂ PO ₄ (pH 7.0) aqueous solution 5 mL
20% MgSO ₄ · 7H ₂ O aqueous solution 0.5 mL
Vitamin solution 20mL
Mineral solution 40mL
NaHCO ₃ 10g
Yeast extract 0.2g

Vitamin solution composition (mg / L)
Biotin 2
Folic acid 2
Pyridoxine hydrochloride 10
Thiamine hydrochloride 5
Riboflavin 5
Nicotinic acid 5
Pantothenic acid Ca 5
Vitamin B12 0.01
p-Aminobenzoic acid 5
Thioctic acid 1

Mineral solution composition (g / L)
Nitrilotriacetic acid 0.25
MnSO ₄ · 4H ₂ O 0.25
NaCl 0.5
FeSO ₄ · 7H ₂ O 0.05
CoCl ₂ · 6H ₂ O 0.09
CaCl ₂ · 2H ₂ O 0.07
ZnSO ₄ · 7H ₂ O 0.09
CuSO ₄ 0.03
AlK (SO ₄ ) ₂ · 12H ₂ O 0.009
H ₃ BO ₄ 0.005
NaMoO ₄ · 2H ₂ O 0.006

The present invention is useful for the production of organic substances by anaerobic microorganisms using gaseous resources as raw materials. In the present invention, a plurality of gas resources having different solubility in an aqueous medium can be efficiently supplied to the aqueous medium, and conditions suitable for the production of organic substances by anaerobic microorganisms can be easily maintained. Moreover, the anaerobic atmosphere required for the growth of anaerobic microorganisms can be easily maintained by gas exchange. The production of organic matter utilizing the activity of anaerobic microorganisms can be carried out more easily and stably industrially, and the cost of the produced organic matter can be reduced. Anaerobic microorganisms that utilize gaseous resources to produce organic substances such as various organic acids including acetic acid are known. The present invention can be widely applied to organic substance production methods using these anaerobic microorganisms.
Furthermore, carbon dioxide is assimilated as an organic substance before being released to the atmosphere, and as a result, it can be used as a technique for fixing carbon dioxide in the atmosphere.

Claims (32)

(1) Anaerobic microorganisms that produce organic substances by assimilating either or both of H ₂ and (2) CO ₂ and CO are anaerobically cultured in an aqueous medium, and are contributed by the microorganisms that accumulate in the aqueous medium. A method for producing an organic substance for recovering the converted organic substance from the aqueous medium, comprising the following steps:
(a) contacting the aqueous medium with a gas phase containing at least one gas of H ₂ , CO ₂ , and CO through a gas permeable membrane that allows permeation of the gas; Forming an interface for gas exchange with
at the interface of the (b) (a), and H _2, CO _2, and CO and 0 ₂ of the respective partial pressures respectively a1, a2, a3 and a4 in the gas phase, the pressure possessed by the gas contained in the aqueous medium Is b1, b2, b3 and b4, the partial pressure on the gas phase side is maintained at a1> b1, a2> b2, a3> b3, and a4 <b4, and the gas phase is separated from the interface of (a). Absorbing the gas in the aqueous medium and dispersing oxygen in the aqueous medium in the gas phase; and
(c) A step of recovering the assimilated organic matter accumulated in the aqueous medium from the aqueous medium. The method according to claim 1, wherein the gas permeable membrane is a gas permeable membrane made of a hydrophobic material. The hydrophobic material is any material selected from the group consisting of polyethylene / PE, polypropylene / PP, polytetrafluoroethylene / PTFE, poly-4 methylpentene 1, and silicone rubber, or a composite material thereof. Item 3. The method according to Item 2. The hydrophobic material is made of any material selected from the group consisting of polyethylene / PE, polypropylene / PP, and polytetrafluoroethylene / PTFE, or a composite material thereof, and the hydrophobic material or the composite material thereof The method according to claim 3, wherein the gas permeable membrane is a microporous membrane. The method according to claim 1, wherein the gas phase is composed of a gas from which O ₂ has been removed. The method according to claim 1, further comprising a step of maintaining an O ₂ partial pressure of a gas constituting the gas phase at 3 kPa or less. The gas constituting the gas phase contains (1) H ₂ and (2) either or both of CO ₂ and CO, and the ratio (molar ratio) of (1) H _{2 to} the gas is (2) The method according to any one of claims 1 to 4, which is equal to or more than the sum of CO ₂ and CO. The method according to claim 1, further comprising a step of circulating a gas constituting the gas phase in the gas circuit. The method according to claim 8, further comprising the step of removing O ₂ from the gas in the gas circuit in the gas circuit in which the gas constituting the gas phase circulates. The method according to claim 9, wherein the step of removing O ₂ is a step of bringing a gas constituting a gas phase into contact with an O ₂ absorbent in a gas circuit. In the gas circuit in which the gas constituting the gas phase circulates, H ₂ is recovered from the gas in the gas circuit, the recovered H ₂ is circulated again in the gas circuit, and the remaining gas that could not be recovered is discarded. 11. A method according to any one of claims 8 to 10 additionally comprising steps. In the gas circuit in which the gas constituting the gas phase circulates, an additional step of newly supplying at least one gas selected from the group consisting of H ₂ , CO ₂ , and CO to the gas constituting the gas phase 12. A method according to any one of claims 8 to 11 comprising. The step of maintaining the partial pressure of the volatile component of the gas constituting the gas phase equal to the liquid phase in a gas circuit in which the aqueous medium contains a volatile component and the gas constituting the gas phase circulates. The method according to claim 12. The method according to claim 13, wherein the volatile component is water and the moisture pressure of the gas constituting the gas phase is kept equal to the liquid phase. An aqueous medium containing anaerobic microorganisms is partitioned by a filtration membrane that allows permeation of the aqueous medium, the anaerobic microbial cells are held in the compartment, and the aqueous medium that has permeated the filtration membrane is the gas-permeable membrane. The method according to claim 1, wherein the method is brought into contact with the gas phase via The method according to claim 15, wherein the filtration membrane is a microfilter or an ultrafiltration membrane. A step of circulating the aqueous medium in the aqueous medium circuit, wherein the filtrate and the gas phase are brought into contact with each other through the gas permeable membrane in the aqueous medium circuit, and the filtrate in contact with the gas phase is obtained. The method according to claim 15 or 16, wherein the method returns to the anaerobic microorganisms retained in the filtration membrane. The method according to any one of claims 1 to 4, wherein the aqueous medium containing anaerobic microorganisms contacts the gas permeable membrane while containing the anaerobic microorganisms. 5. The gas permeable membrane according to claim 1, wherein the gas permeable membrane is a hollow fiber having the gas permeable membrane as an outer wall, a gas is disposed inside the hollow fiber, and an aqueous medium is disposed outside the hollow fiber. Method. The method according to claim 19, wherein the gas inside the hollow fiber is moved, the aqueous medium outside the hollow fiber is also moved, and the moving directions of both are opposed. The method according to claim 19 or 20, wherein turbulent flow is applied to an aqueous medium flowing outside the hollow fiber. An anaerobic microorganism that produces organic matter by assimilating one or both of (1) H ₂ and (2) CO ₂ and CO, containing the following components: Organic matter production equipment for producing organic matter in it;
(1) A gas permeable membrane that allows permeation of the gas to a gas phase containing at least one gas of H ₂ , CO ₂ , and CO, wherein the aqueous medium is passed through the gas permeable membrane and the other A gas permeable membrane that forms an interface where gas exchange takes place between the two when the gas phase is disposed in
(2) a gas circuit connected to the gas permeable membrane of (1) and circulating a gas constituting a gas phase containing at least one gas of H ₂ , CO ₂ , and CO; and
(3) An aqueous medium circuit that is connected to the gas permeable membrane of (1) and circulates the aqueous medium. The apparatus according to claim 22, wherein the gas permeable membrane is a gas permeable membrane made of a hydrophobic material. The hydrophobic material is any material selected from the group consisting of polyethylene / PE, polypropylene / PP, polytetrafluoroethylene / PTFE, poly-4 methylpentene 1, and silicone rubber, or a composite material thereof. Item 24. The apparatus according to Item 23. 25. The gas permeable membrane according to any one of claims 22 to 24, wherein the gas permeable membrane is a hollow fiber having the gas permeable membrane as an outer wall, a gas is disposed inside the hollow fiber, and an aqueous medium is disposed outside the hollow fiber. apparatus. The apparatus according to claim 25, wherein a plurality of the hollow fibers are packed in a column, and the aqueous medium circulates in the column. 27. The apparatus according to claim 25 or claim 26, wherein a gas circulating inside the hollow fiber is opposed to a circulation direction of an aqueous medium circulating outside. 28. An apparatus according to any one of claims 22 to 27, wherein an oxygen absorbent is disposed in the gas circulation circuit. 30. The device of claim 28, wherein the oxygen absorbent is a liquid. The gas circulation circuit additionally includes hydrogen recovery means, and hydrogen recovered from the gas in the gas circulation circuit by the hydrogen recovery means is circulated again to the gas circulation circuit, and residual gas that could not be recovered is recovered. 30. Apparatus according to any one of claims 22 to 29 for disposal. The microbe holding section which holds the anaerobic microbial cells arranged in the aqueous medium circuit of (3) and which is permeated by a filtration membrane which allows permeation of the aqueous medium is additionally included. The apparatus in any one of. The organic medium extraction means is further provided in the aqueous medium circuit for recovering the organic substance assimilated by the microorganisms accumulated in the aqueous medium from the aqueous medium recovered from the microorganism holding compartment through the filtration membrane. 31. Apparatus according to 31.

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