JPH04197192A - Production of xylose and reduced xylose - Google Patents

Abstract

PURPOSE:To obtain the subject compound having high purity and useful as a color-improving agent for fish paste product, etc., on an industrial scale at a low cost by popping or steaming bagasse, hydrolyzing the residue with an acid, neutralizing with an alkali and fermenting the sugars other than xylose in the neutralized liquid with a microorganism. CONSTITUTION:Bagasse is popped or steamed, the soluble component is removed by washing with water, the residue is hydrolyzed with an acid such as sulfuric acid under heating and the acid hydrolysis liquid is neutralized to pH 6.0 with calcium hydroxide, etc. The neutralized liquid is added with pressed baker's yeast (Saccharomyces cerevisiae) and maintained at 30 deg.C for 30min under stirring to effect the fermentation of sugars other than xylose in the neutralized liquid and obtain high-purity xylose. The xylose is reduced by hydrogenating with a Raney-Ni catalyst to obtain xylitol which is a reduction product of xylose.

Description

[Detailed Description of the Invention] [Background of the Invention] Technical Field The present invention relates to a method for producing xylose and its reduced product, and more particularly, to a method for producing xylose and its reduced product, which is highly pure xylose and its reduced product using bagasse as a raw material. This invention relates to an efficient method for producing xylitol.

<Prior Art> Conventionally, xylose or xylitol has been produced from plants with high xylan content, such as cottonseed husks, wood (for example, hardwood such as birch), and corn cobs.

A technique for producing xylose or xylitol using bagasse as a raw material is introduced in, for example, JP-A-49-55856.

In addition, regarding the method of removing unnecessary sugars other than xylose that are mixed in during the process, in the production of xylose and xylitol or the production of products with high fructooligosaccharide content,
A method of reducing hexoses, especially glucose, using specific yeasts and lactic acid bacteria is known (Japanese Patent Publication No. 1983).
-13768 publication, chemical products of rl1290, Kagaku Kogyo Nipposha (1990) p, 1187J, JP-A-1983-
No. 14792), there is no mention of removal of arabinose.

On the other hand, a method for producing highly pure xylose using bagasse as a raw material has also been reported (■ "Satoshi Yoshizumi, Food Industry,
3, vol. 39-43.1971J and ■ "Jun Mizuguchi, Minoru Ohashi, Stratification, 24.219-222.1950J).

<Problems to be Solved by the Inventor> However, problems remain in producing xylose or xylitol using bagasse as a raw material. For example, when attempting to produce xylose using the method described above using bagasse as a raw material, bagasse contains many sugars other than xylose as its constituent sugars, so various sugars such as glucose and arabinose other than xylose are present in the acid decomposed solution. are extracted in large numbers. Removal of these sugars is complicated and difficult using conventional mechanical methods such as chromatography, and
Production of xylitol by this method is difficult because removal requires a great deal of expense.

In addition, methods ① and ① above involve extraction with alkali, recrystallization, or crystallization using a solvent in order to extract xylan with high purity and remove the other contaminating sugars mentioned above. This method is not satisfactory in terms of cost or labor.

[Summary of the invention]

Summary of the Invention The purpose of the present invention is to solve the above-mentioned problems, efficiently produce highly pure xylose from bagasse, and reduce the xylose to produce xylitol.

The present inventors used bagasse as a raw material and adopted a specific process, particularly explosion or steaming, which was conventionally used to extract xylan, as a process for extracting and removing impurities. We have discovered that xylose can be efficiently obtained by decomposing and removing it with microorganisms, and that xylitol can be easily obtained from this xylose by conventional reduction, and based on this knowledge, we have completed the present invention.

That is, the method for producing xylose according to the present invention is characterized in that the following steps (1) to (4) are performed sequentially.

(1) The first step of crushing or steaming bagasse, (2
) a second step of acid hydrolyzing the residue obtained in step ji11, (3) a third step of neutralizing the acid hydrolysis solution obtained in the second step with an alkali, and (4) a third step of acid hydrolyzing the residue obtained in the third step. A fourth step in which sugars other than xylose in the neutralized solution are fermented by microorganisms.

Furthermore, the method for producing xylitol according to the present invention is characterized in that xylose obtained as described above is reduced.

Effects> According to the present invention, by removing impurities by blasting or steaming in the first step, the cost of chemicals such as alkalis or acids for extracting and removing impurities, which were conventionally used, is no longer required. Instead, the operation time for this can be shortened.

By using microorganisms in the fourth step to remove unnecessary sugars such as glucose and arabinose, the purity of xylose is increased and the conventionally required recrystallization and crystallization using a solvent are no longer necessary.

Therefore, by the production method according to the present invention, it has become possible to efficiently produce highly pure xylose and xylitol using bagasse as a raw material.

[Detailed description of the invention]

The method for producing xylose according to the present invention includes steps (1) to (
4), namely (1) the first step of crushing or steaming bagasse; (2)
) a second step in which the residue obtained in the first step is acid-hydrolyzed; (3) a third step in which the acid-hydrolyzed solution obtained in the second step is neutralized with an alkali; and (4) in the third step. As mentioned above, this method is characterized by sequentially carrying out the following four steps: a fourth step of fermenting sugars other than xylose in the obtained neutralized liquid by microorganisms; After the necessary residue is obtained by solubilizing impurities by crushing or steaming the bagasse, this residue is treated with acid hydrolysis to obtain an extract containing xylose. The basic principle is to obtain xylose by fermenting and decomposing other unnecessary sugars and removing them.

■) Production of xylose (1) Raw materials Bagasse as used in the present invention refers to lees obtained by squeezing sucrose from sugarcane stalks. Specifically, for example,
It is the lees obtained by squeezing cane juice from sugarcane by countercurrent extraction, and is usually obtained at a sugar factory with a moisture content of about 50%.

(2) First step A step in which impurities are solubilized without significant loss of xylan and the necessary residue is obtained by crushing or steaming the above bagasse (usually about 50% water content) under appropriate conditions. It is. If the treatment conditions are too strong, i.e., at high pressure and for a long time, the decomposition of xylan will proceed and the yield of xylose obtained in the subsequent step will decrease; if the treatment conditions are too weak, i.e., at low pressure, Under short-time treatment conditions, removal of impurities will be insufficient and the purity of xylose will be low.

Explosion in the present invention means that the object to be treated (i.e., bagasse) is kept in high-temperature, high-pressure steam for a certain period of time, and then -
This is a chemical and physical treatment method by releasing air under atmospheric pressure, and the operating conditions are determined by water vapor pressure (temperature is primarily determined by water vapor pressure) and retention time. Preferred processing conditions for blasting are water vapor pressure of 5 to 28 kg/c and a holding time of 30 seconds to 20 minutes, more preferably water vapor pressure of 5 to 15 kg/c and a holding time of 1 to 10 minutes. .

By setting such preferable treatment conditions, it is possible to reduce the loss of xylan due to excessive progress of xylan decomposition and extract and remove impurities, thereby further increasing the yield or purity of xylose obtained in subsequent steps. can. For a general description of blasting and the production of xylose through xylan extraction using blasting, see Mitsuhiko Tanahashi, Takamasa Higuchi, Polymer Processing, 32, vol. 12.5.
95-803, 1983J.

``Steaming in the present invention is a method in which the object to be treated is held in high-temperature, high-pressure steam for a certain period of time, and then the pressure is slowly reduced to atmospheric pressure. The difference between this and explosion is that in steaming, high-pressure steam is not released all at once to atmospheric pressure, and the operating conditions are determined by steam pressure (temperature is uniquely determined by steam pressure) and retention time, just like in explosion. Ru.

The preferred processing conditions for steaming are a water vapor pressure of 2 to 15 kg/
cd and a retention time of 5 to 80 minutes, more preferably a water vapor pressure of 4 to 8 kg/c and a retention time of 10 to 6 minutes.
It is 0 minutes.

By setting such preferable processing conditions, it is possible to reduce the loss of xylan due to excessive progress of xylan decomposition, as in the case of explosion, and increase the yield or purity of xylose obtained in the subsequent process. For general descriptions of steaming, see ``Food Equipment Practical Comprehensive Editorial Committee, Food Equipment Practical Comprehensive, Sanei Research Association Publishing Department (1981
) P, 114-115) J.

Desirably, the necessary xylan is obtained by crushing or steaming under the above-mentioned processing conditions, followed by solid-liquid separation using a centrifuge or filter, and further washing with water as necessary to remove impurities. A residue containing purity can be obtained.

(3) Second step This is a step in which the residue obtained in the first step is acid-hydrolyzed under appropriate conditions to obtain a hydrolysis solution containing xylose.

In this process, if the acid hydrolysis conditions are too strong, i.e. insufficient amount of acid added, high pressure, long time conditions, cellulose other than xylan will be degraded and the xylose purity will decrease; if it is too weak, i.e. acid addition If the amount is insufficient, the pressure is low, and the time is short, xylan cannot be sufficiently decomposed and the xylose yield decreases.

A known method for this purpose can be used for acid hydrolysis, for example, a method in which an aqueous acid solution is added to the residue and heated or pressurized while heating can be applied.

There are no particular restrictions on the acid used for acid hydrolysis, and examples include inorganic acids such as sulfuric acid, hydrochloric acid, and phosphoric acid, and organic acids such as acetic acid and citric acid, but strong acids such as sulfuric acid are preferable from cost considerations. .

The amount of acid added to the residue is preferably 0.2 to 30% (v/
V), more preferably 0.5 to 10% (w/v), and when used, it is desirable to add the acid as a diluted solution dissolved in an appropriate amount of water so that the acid is distributed throughout the residue.

The above heating and pressurization can be carried out by steaming or explosion, and in the case of steaming, preferably the water vapor pressure is 2.
The holding time is 20 to 120 minutes at ~15 kg/cj,
More preferably 4 to 8 kg/c and a retention time of 4
In the case of explosion, the holding time is preferably 30 seconds to 20 minutes at a water vapor pressure of 5 to 28 kg/cd, and more preferably the holding time is 30 seconds to 20 minutes at a water vapor pressure of 5 to 10 kg/cd. 1 to 10 minutes.

After acid hydrolysis, preferably under the treatment conditions described above,
By performing solid-liquid separation using a centrifuge, a filter, etc., an extract containing xylose can be obtained.

A general description of this type of acid hydrolysis is provided by Akio Tsukui, Bulletin of Tokyo Kasei Gakuin University, 410°47-50 (
(1970), J.

(4) Third step: In this step, alkali is added to the extract obtained in the second step, and in the next step, this pH is adjusted to a level that allows for microbial treatment, that is, the fermentation and decomposition of unnecessary sugars other than xylose by microorganisms. This is the process of neutralizing the extract.

A known method for this purpose can be used for neutralization, for example, a method of adding an alkali to the extract and stirring it can be applied.

There is no particular restriction on the alkali used for neutralization, and examples include calcium hydroxide, calcium carbonate, aqueous ammonia, and the like. In addition, when sulfuric acid is used in the second step of acid hydrolysis, if a calcium base such as calcium hydroxide or calcium carbonate is used, sulfate ions can be removed as calcium sulfate precipitate. It is possible to reduce the ion exchange load in the purification step that is performed as necessary after the step.

The amount of alkali added can be determined by the pH after neutralization, and the pH may be one that allows microbial treatment in the fourth step. Such pH is preferably 2.5 to 7.0, more preferably 3.5 to 6.5.

Note that if the pH is too high, it will lead to an increase in extra ion exchange load in the purification step that is performed as necessary after the fourth step, and if the pH is too low, the ability of the microorganisms will not be exhibited in the fourth step.

(5) Fourth step This is a step in which sugars other than xylose in the neutralized liquid obtained in the third step are removed by fermentation by microorganisms.

The microorganism that can be used here may be any microorganism that does not assimilate xylose but can assimilate glucose or (and) arabinose, which is contained in a particularly large amount in the neutralization solution. Examples of such microorganisms include brewer's yeast. , baker's yeast (
An example is bacteria. When yeast is used, only glucose is assimilated, but when lactic acid bacteria are used, arabinose and the like can be assimilated in addition to glucose, so the xylose purity can be further increased. Regarding the method of removing unnecessary sugars, there is a known method of reducing hexoses, especially glucose, using specific yeasts and lactic acid bacteria in the production of xylose and xylitol or in the production of products with high fructooligosaccharide content (Tokuko Sho et al. 50-13
Publication No. 768, "11290 Chemical Products, Chemical Industry Daily Pillar (1990) p. 1187 J, JP-A-1983-1
No. 4792), there is no mention of removal of arabinose.

The conditions for microbial treatment, that is, the fermentation and decomposition of sugars other than xylose by microorganisms, may be any conditions as long as they can be suspended in a neutralizing solution and fermentation can be carried out without killing the microorganisms, and the preferable conditions are shown below. ing. Normally, this process can be carried out simply by allowing the neutralized solution in which the microorganisms are suspended to stand at room temperature.

The amount of microorganisms added to the neutralization solution is 0 as the dry weight of microorganisms.
．． 1 to 10.0% (v/w) is preferable, and 0.3 to 2.
0% (v/W) is more preferable. Processing temperature is 15-37
C is preferable, and 25 to 30 C is more preferable. The treatment time is preferably 1 minute to 15 hours, more preferably 10 minutes to 6 hours.

Furthermore, the microorganisms used may be in the form of free microorganisms in a suspension as described above, or may be in the form of immobilized microorganisms immobilized on a carrier by a conventional method.

If the amount of microorganisms added or used is too large, the cost will increase, and if the amount is too small, the processing time will become longer. If the treatment temperature is too high, not only will the microorganisms die and the objective cannot be achieved, but also the contents of the microorganisms will be mixed in due to autolysis, which will increase the ion exchange load in the purification process that is performed as necessary after this fourth step. Connect. Furthermore, although the shorter the treatment time, the better, there is a limit when considering the separation of bacterial cells after treatment, which will be described later. If it is too long, self-digestion of microorganisms will occur, leading to an increase in the ion exchange load in the purification step that is performed as necessary after the fourth step.

Free microbial cells can be removed by commonly used methods such as filtration and centrifugation, and substances produced by microorganisms can be removed by conventional methods, such as concentrating ethanol and removing organic acids such as lactic acid. can be removed with ion exchange resin.

The crudely purified liquid obtained by such microbial treatment can be purified by known methods such as ion exchange and electrodialysis, if necessary, to obtain a xylose solution with a purity of 90 to 98%. As a specific example of such a method, for example, activated carbon is added at a solid content of 1 to 3% (V/W),
After treatment with activated carbon and kept at 0°C for 1 hour, cation exchange resin (e.g. Amberlite IR-120B etc.) and anion exchange resin (e.g. Amberlite IRA-68, IRA
-410, etc.) can be exemplified. For general descriptions of such purification methods, see, for example, "Conversion and Utilization of Hardwood Biomass Resources (198g), edited and published by the Forestry Science and Technology Agency.
9.148-161 J.

The obtained xylose solution can also be crystallized or powdered by conventional methods, if necessary.

2) Production of xylitol The method for producing xylitol according to the present invention is to obtain xylitol by reducing the xylose or xylose solution obtained in the fourth step in the production of xylose.

Reduction of xylose can be carried out by conventional methods. Specifically, for example, in the presence of a Raney nickel catalyst, the xylose concentration is 10 to 75%, the temperature is 5° to 200°C, and the hydrogen pressure is 2.
Xylitol can be obtained by applying the condition of ~250 kg/c- (Methods in
Carbohydrate Chemistry:
Roy L, vhistler and M, L, Wo
lfroi, Academic Press Inc.
, vol. II, 77-79 (1963)).

The crude xylitol solution obtained by the reduction is purified by ordinary purification methods such as ion exchange, if necessary, and then crystallized by ordinary methods (for example, see Japanese Patent Publication No. 45-37817) to obtain crystalline xylitol. can do. The xylitol thus obtained has a purity of 99.
It is 5% or more.

Moreover, the xylitol solution obtained by reduction can be purified by ion exchange or the like as necessary, and then powdered by a conventional method to obtain powdered xylitol.

According to the production method of the present invention as described above, in the first step, sugars such as glucose and arabinose are partially eluted and removed, and the xylose purity of the extract obtained in the second step is increased. Furthermore, in the fourth step, sugars other than xylose are removed by microorganisms, increasing xylose purity.

Therefore, highly purified xylose can be efficiently obtained from bagasse, and xylitol can be easily produced by reducing the xylose.

The obtained xylose can be used as a color improver for sosan paste products and for processing meat, etc.

In addition, the obtained xylitol can be used as a stabilizer for infusions and other purposes.
It can be used as a pharmaceutical raw material such as an excipient, and as a food additive such as a sweetener.

〔Example〕

Example 1 As a raw material, 9.26 kg (dry weight) of bagasse was
As a process, blasting was carried out under conditions of maintaining a water vapor pressure of 10 kg/c for 3 minutes, and then soluble materials were removed by washing with water to obtain a residue.

In the second step, an acid aqueous solution prepared by dissolving 200 g of sulfuric acid in 261 water was added to the residue, and the mixture was steamed at a water vapor pressure of 6 kg/cj for 80 minutes. ) was obtained.

As the third step, calcium hydroxide is added to the extract, and p
Adjusted to H6.0.

As the fourth step, Lactobaillus was added to the neutralization solution.
bre-vis (bacteria cells that have been cultured in MR5 medium, which is commonly used for lactic acid bacteria culture, and then washed with water) 90
After adding 0 g (dry weight) and keeping at 30°C for 5 hours with stirring, the bacterial cells were removed by centrifugation.

After that, 19.5 g of activated carbon was added and kept at 60°C for 1 hour, and the activated carbon was removed by filtration.
R-120B (manufactured by Organo Co., Ltd.) H type 71 and Amberlite IRA-410 (manufactured by Organo Co., Ltd.)
After deionization and purification using OH type 141, it was concentrated under reduced pressure.

When this concentrated solution was measured by high performance liquid chromatography, it was found that it contained 879.7 g of xylose, and the xylose purity in the solid content was 95.0%.

Example 2 A commercially available Raney nickel catalyst 3.0 was added to 500 g of the xylose obtained in Example 1 as a 10% aqueous solution.
g was added thereto, and the mixture was placed in a magnetically stirred stainless steel autoclave having an internal volume of 11.

This was filled with hydrogen gas up to 100 kg/cd, and 16
The reaction was allowed to proceed at 0°C for 2 hours with stirring.

After catalyst filtration, the filtrate was filtered using Amberlite IR-120B (
Organo Co., Ltd.) H type 120m1 and Amberlight IRA-410 (Organo Co., Ltd.) OH type 24
Deionized and purified with 0ml, 58g of deionized solution under reduced pressure
By concentrating the mixture to a concentration of 87% and standing overnight, colorless xylitol crystals were precipitated. Filter and dry this to crystallize xylitol.35. I got og.

Example 3 The process was carried out in the same manner as in Example 1, except that instead of the blasting in the first step of Example 1, steaming was carried out under conditions of maintaining the water vapor pressure at 6 kg/c for 40 minutes, and 870.4 g of xylose was A concentrated solution was obtained.

The xylose purity in the solid content was 95.1%.

Example 4 To 500 g of a 50% aqueous solution of xylose obtained in Example 3, 10.0 g of a commercially available Raney nickel catalyst was added.
was added, placed in a magnetically stirred stainless steel autoclave with an internal volume of 11, and filled with hydrogen gas to 100 kg/cd.
The reaction was carried out at 150° C. for 2 hours with stirring.

After catalyst filtration, deionization was performed in the same manner as in Example 2, and the concentration was 80%.
After concentrating the mixture to 45° C., 0.1 g of xylitol crystals was added thereto, and the mixture was cooled to 18° C. over 24 hours to obtain xylitol massit.

Next, 142.5 g of xylitol crystals were obtained by compacting the obtained xylitol mass kit.

The purity of this xylitol was 99.8% as measured by high performance liquid chromatography.

Example 5 As a raw material, 92.6 g (dry weight) of bagasse was exploded in the first step under conditions of maintaining the steam pressure at 10 kg/cd for 5 minutes, and the soluble materials were washed away with water to obtain a residue.

As the second step, an acid aqueous solution prepared by dissolving 2 g of sulfuric acid in 100 ml of water was added to the residue, and the water vapor pressure was 6 kg/c.
The mixture was blasted under conditions of holding for a minute to obtain extract liquid 21 (including the water used for washing out from the blasting device).

As the third step, calcium hydroxide is added to the extract, and p
Adjusted to H6.0.

Add vis40g (dry weight) and heat to 30°C while stirring.
After keeping for 2 hours, the bacterial cells were removed by centrifugation.

After that, 0.2g of activated carbon was added and kept at 60℃ for 1 hour, and the activated carbon was removed by filtration.
-120B (manufactured by Organo Co., Ltd.) H type 70 ml and Amberlite I RA-410 (Organo Co., Ltd.) OH type 140 ml were used for deionization and purification, followed by concentration under reduced pressure.

When this concentrated solution was measured by high performance liquid chromatography, it was found that it contained 9.4 g of xylose, and the xylose purity in the solid content was 94.2%.

Example 6 As a raw material, bagasse 92. In the first step, 6 g (dry weight) was exploded under conditions of maintaining a water vapor pressure of 10 kg/cd for 3 minutes, and the soluble matter was removed by washing with water to obtain a residue.

As the second step, an acid aqueous solution prepared by dissolving 2 g of sulfuric acid in 260 ml of water was added to the residue, and the water vapor pressure was 6 kg/cd.
Steaming was carried out under conditions of holding for 0 minutes to obtain extract 21 (including the water used for washing out from the steamer).

The third and subsequent steps were carried out in the same manner as in Example 5 to obtain a concentrated solution containing 9.8 g of xylose. The xylose purity in the solid content was 95.2%.

Example 7 The fourth step in Example 6 was carried out using commercially available compressed baker's yeast (Sac
charoa+yces 5erev1s1ae) 3
Add 0 g (dry weight) and heat to 30°C while stirring.
A concentrated solution containing 10.6 g of xylose was obtained by carrying out the same treatment as in Example 5, except that the bacterial cells were removed by centrifugation after being maintained for 0 minutes. The xylose purity in the solid content was 90.2%.

Applicant's representative: Mr. Sato

Claims (1)

[Scope of Claims] 1. A method for producing xylose, which comprises sequentially carrying out the following steps (1) to (4). (1) The first step of crushing or steaming the bagasse, (2) The second step of acid hydrolyzing the residue obtained in the first step, (3) The acid hydrolysis solution obtained in the second step is treated with an alkali. a third step of neutralizing; and (4) a fourth step of fermenting sugars other than xylose in the neutralized liquid obtained in the third step using microorganisms. 2. A method for producing xylitol, which comprises reducing the xylose obtained by the method according to claim 1. 3. In the first step, the explosion is carried out at a vapor pressure of 5 to 28 kg/cm^
3. The manufacturing method according to claim 1, wherein the manufacturing method is carried out under conditions of 2 and a holding time of 30 seconds to 20 minutes. 4. Steam pressure in the first step is 2 to 15 kg/cm^
3. The manufacturing method according to claim 1, wherein the manufacturing method is carried out under conditions of 2 and a holding time of 5 to 80 minutes. 5. The microorganism in the fourth step is Saccharomyces.
Lactobacillus cerevisiae
Lactobacillus brevis, Lactobacillus cel
lobiosus and Lactobacillus
one or two selected from the group consisting of
The manufacturing method according to any one of claims 1 to 4, wherein the manufacturing method is more than one species.