JP2001275693A - Method for producing saccharide solution of high concentration and fermentation production process for amino acids using the saccharide solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a saccharified solution of high concentration through direct saccharification of tapioca starch from cassava without purification of the starch and a method for carrying out the amino acid fermentation by using the resultant saccharified solution. SOLUTION: The cassavas are peeled and dried to lower the water content to <=16 wt.% and the dried cassavas are crushed into particles of <=150 μm, suspended in water to prepare a crude starch slurry of >=35 wt.%. Then, a starch liquefying enzyme and a saccharifying amylase are allowed to act on the slurry to produce the saccharified solution of high concentration. The resultant saccharified solution is used to carry out the amino acid fermentation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a high-concentration sugar solution by directly saccharifying tapioca starch from cassava potato tissue without separating and purifying the same, and an amino acid using the high-concentration sugar solution as a fermentation raw material. And a method for producing by fermentation.

[0002]

2. Description of the Related Art Tapioca is a starch produced from cassava potato, which is converted into glucose by enzymatic saccharification.
It is used as a main raw material for various fermented products such as amino acids.

[0003] Conventionally, tapioca has been obtained by pulverizing cassava potato as a raw material, extracting fine starch particles stored in the potato with water, straining it with a fine mesh or centrifuging to remove fibers other than starch. It is manufactured by separating and collecting from scum and drying. Usually, raw cassava potato (raw potato)
Contains about 50% of water, and 20-25
% Of tapioca is obtained, and almost the same amount of scum is discharged at present.

[0004]

However, when the starch content of cassava potato was analyzed, 40-45% of the raw potato was starch, and therefore, a considerable amount of starch was not extracted, and the discharged fiber Etc. will remain in the residue.

[0005] The cassava potato is usually crushed by a sawtooth tooth-implanting grinder (raspar) or the like. However, since the cell membrane is thicker and the starch particles are smaller than potatoes, the grinding efficiency is slightly lower and the starch particles are smaller. It is not sufficient for separation and no remarkable improvement in starch yield is observed. In fact, when the scum is observed with a scanning electron microscope, it can be clearly seen that almost homogeneous and spherical starch granules are present and many starch particles are covered with a film-like material.

[0006] In order to reproduce the same state as the crushing of cassava potato in a laboratory, cassava potatoes were grated with a grater according to a flow sheet shown in FIG. 1, and a starch production experiment was carried out. Each weight of starch and scum was measured to determine the starch yield (extraction rate). Table 1 shows the results of three experiments performed under the same conditions.

[0007]

[Table 1]

[0010] As shown in Table 1, the starch weight and the scum weight obtained in each case are almost the same, and almost the same amount of scum as the product tapioca is discharged from the actual tapioca starch factory. Well matched with the situation.

As described above, a large amount of starch particles remain in the scum and are covered with a film-like material, so that the ordinary crushing process for collecting starch similarly imposes a great limitation on the yield of starch. As a result, the starch in the cassava potato cannot be sufficiently extracted. This is not only because the starch resources in cassava potatoes are not being used effectively, but also because there is still a large amount of starch in waste such as scum discharged from starch manufacturing plants. May be connected.

[0010] Therefore, if a high-concentration saccharified liquid was produced by directly saccharifying the cassava potato without passing through the starch extraction step and used as a fermentation raw material, it was generated during the production of cassava potato starch. It is thought that this will greatly reduce the amount of scum and eventually resolve pollution problems.

The present invention has been made in view of such a viewpoint, and a method for producing a high-concentration saccharified solution by directly saccharifying tapioca starch from cassava potato without separation and purification, and a method for producing the high-concentration saccharified solution It is intended to provide a method for producing an amino acid by fermentation using the same.

[0012]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, peeled cassava potato and dried it so that its water content was 16% by weight or less. Found that it was possible to easily pulverize, and by this pulverization, the film covering the starch particles was broken and the starch therein could also be saccharified. That is, the water content is 16% by weight.
The cassava potato dried below is finely pulverized to a particle size of 150 μm or less, so that the powder has good suspension properties and maintains a smooth fluidity even at a high slurry concentration of 35%. It is easy to handle, and liquefaction and saccharification are carried out smoothly. More than 80% of starch in powder is saccharified,
A sugar solution with a high concentration of 40% or more, which can be used as a fermentation feed solution, is obtained.
When suspended in water for saccharification, if pre-liquefaction treatment is performed using cellulase, the powdered potato can be concentrated at a high concentration (45 to 55 g).
/ Dl), and further, when the cassava potato powder is suspended in water for liquefaction and saccharification,
By adding the liquefaction enzyme in advance, it is possible to obtain a high concentration (45 g / dl) without heating to a temperature at which liquefaction enzyme activity is high.
Powder can be suspended, and subsequent liquefaction and saccharification can be performed smoothly, and this sugar solution is suitable as a raw material for amino acid fermentation, amino acids can be obtained in high yield, and starch of cassava potato can be obtained. It has been found that the utilization rate can be greatly increased and the amount of waste can be reduced. The present invention has been made based on such findings.

That is, according to the first aspect of the present invention, dried cassava potato having a water content of 16% by weight or less by peeling and drying is crushed to 150 μm or less, and this is suspended in water to obtain 3%.
A method for producing a high-concentration sugar solution, comprising preparing a crude starch slurry containing 5% by weight or more of starch and then reacting with a starch liquefying enzyme and a saccharifying enzyme to liquefy and saccharify the enzyme. In the invention of the present invention, dried cassava potatoes having a water content of 16% by weight or less by peeling and drying are used.
Pulverized to not more than μm, suspended in an aqueous solution containing cellulase and subjected to enzymatic treatment with cellulase, 35% by weight
After preparing a crude starch slurry containing the above starch, a method for producing a high-concentration sugar solution, characterized in that enzyme liquefaction and enzymatic saccharification by acting starch liquefaction enzyme and saccharification enzyme,
The invention according to claim 3 is characterized in that the water content is reduced to 16 by peeling and drying.
The dried cassava potatoes having a weight percentage of not more than 150% are crushed to 150 μm or less and suspended in an aqueous solution containing a starch liquefying enzyme to prepare a crude starch slurry containing not less than 35% by weight of starch. A method for producing a high-concentration saccharide solution characterized by enzymatic saccharification by the action of an enzyme, wherein the invention of claim 4 is characterized in that the dried cassava potato has a water content of 5 to 10% by weight. A method for producing a high-concentration sugar solution according to any one of claims 1 to 4, wherein the invention according to claim 5 uses the high-concentration sugar solution produced by the method according to any one of claims 1 to 4 as a fermentation raw material. This is a method for producing amino acids by fermentation.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Raw cassava potato used as a raw material has a large deterioration in quality after harvesting, so it can be preserved by immediately peeling and drying, and the peeled and dried potato is powdered by a crusher to make tapioca starch. A similar fine powder can be used. The starch content per dry matter is about 90%, and thus it is a starch-based crude starch powder.

Cassava potato having a water content of 16% or less is crushed into particles of 1 to 10 mm using a crusher according to a conventional method. Subsequently, it is pulverized to 150 μm or less. Apparatuses for performing pulverization during large-scale processing on an industrial scale include a homogenizer and a ball mill.

The smaller the water content of the powder, the higher the weight ratio of the powder having a size of 150 μm or less, and the easier it is to liquefy and saccharify. Therefore, the water content is 16% by weight or less, preferably 5 to 10% by weight. Dry powder is used.

The pulverized powder having a size of 150 μm or less has good suspension properties, maintains good fluidity even at a slurry concentration of 45%, and has a low viscosity of 500 centipoise or less, and has good operability. By making the particles finer, advantages such as a shorter liquefaction time and easier handling of the liquid can be enjoyed.

The powdered cassava potato can be directly liquefied and saccharified using a starch liquefying enzyme and a saccharifying enzyme, like tapioca starch. When the powder of dried potato is liquefied and saccharified, the starch becomes glucose and is solubilized, but components other than starch such as cellulose remain as solids. Can be easily removed.

When the dried cassava potato powder is suspended in water, if it is subjected to an enzymatic treatment with cellulase before liquefaction, it can be suspended at a high concentration, liquefaction and saccharification are promoted, and the saccharification rate is reduced. As a result, the amount of the residue is reduced, and the adverse effect of the residue when the sugar liquid is used as a fermentation raw material can be prevented.

If the whole amount of the dried cassava potato powder to be liquefied into the cellulase-containing solution is not added all at once but is added in small portions, the suspension can be suspended at a high concentration of 45 to 55 g / dl, so that 40 to 45% Can be produced.

By acting cellulase, the membrane covering the starch particles is enzymatically degraded, resulting in liquefaction of the starch.
It is considered that saccharification is effectively performed. As the cellulase, a commercially available cellulase such as “CELLULASE YC” (trade name, manufactured by Kikkoman Corporation) can be used, and a cellulase produced by a fungus of the genus Trichoderma is preferably used. The amount used may be about 10 units or more in the filter paper disintegration activity (FPA: see Jinjinshokan "Enzyme Utilization Handbook", pp. 297-298). It is 100 units or more, preferably 300 to 1500 units per gram of powder. The reaction is carried out at a temperature in the range of 40-50 ° C. and pH 5-7. The reaction time may be generally about 2 to 4 hours.

After performing the cellulase reaction, a liquefying enzyme, for example, "T-5" (trade name, manufactured by Daiwa Kasei Co., Ltd.) is added to powder 1
It is added so as to be 20 per g, and the mixture is heated and stirred at 85 to 95 ° C. for 1 hour. After allowing to cool and adjusting the pH to 4.2 with dilute sulfuric acid, the saccharifying enzyme, for example, “NC-
4.2 "(trade name, manufactured by Amano Pharmaceutical Co., Ltd.) in an amount of 2 to 5 units per 1 g of powder, heated to 55 to 65 ° C, and heated and stirred for 40 to 48 hours while maintaining the same temperature. To complete the enzymatic reaction.

When suspending the dried cassava potato powder in water, liquefaction proceeds more quickly if 20 units / g of powdered liquefaction enzyme are added in advance. Also, without heating to 90 ° C., where liquefaction enzyme activity is high, liquefaction / saccharification efficiency is increased by gradually adding powder to a liquefaction enzyme-containing solution at 40 to 60 ° C., and high concentration (45 to 55 g / dl) is obtained. The powder can be saccharified to produce a sugar solution having a glucose concentration of 40 to 45 g / dl.

The relationship between the particle size of the dried peeled potato powder, the saccharification ratio and the residue ratio is shown in Experimental Example 1 below.

Test Example 1 Immediately after harvesting potatoes from Lampung, Indonesia, the potatoes were peeled, dried in the sun until the weight was reduced to 2/3, and further dried for 40 days.
The mixture was dried under reduced pressure at about 24 ° C. for about 24 hours until no change in weight was observed. The water content of this powder was about 5%. The powder was acid-decomposed (7.6N HCl was added and heated in boiling water for 2 hours), and the starch content as glucose was determined by HPLC. The starch content in the powder was 89.4%.
Met.

A dried potato of about 10 to 20 cm in length is 1 cm.
Crushed to ² and the desktop blender "Osterizer"
16-speed "[SUN BEAM OSTER
Manufactured by the company).

The pulverized powder is classified into four types that have passed through 9, 16, 40, and 100 meshes, respectively, and 5 g of the powder having each particle size is previously liquefied enzyme "T-5" (manufactured by Daiwa Kasei Co., Ltd.) ( (20 units / g of powder) was added in five portions while stirring. After completion of the addition, the mixture was further reacted for 1 hour in boiling water while shaking and stirring. The mixture was allowed to cool to room temperature, and the pH was adjusted to 4.2 with dilute sulfuric acid. The saccharification enzyme "NC-4.2" was added in 3 units per 1 g of powder, heated to 60 ° C, and stirred at the same temperature for 48 hours. The liquid after completion of saccharification was centrifuged, and the saccharification rate and residue ratio of the saccharified liquid were analyzed.

As a result of examining the relationship between the particle size, the saccharification ratio and the residue ratio, as shown in Table 1, the smaller the particle size, the smoother the saccharification, and by grinding to a particle size of 150 μm or less, 82% of the powder is reduced. Glucose is obtained and 9 of the starch content
It can be seen that 4% was saccharified.

[0029]

[Table 2]

Next, the moisture content of the dried peeled potatoes and the 100-mesh pass (%) when crushed for a certain time using a crusher.
Is shown in Experimental Example 2.

Experimental Example 2 Desktop blender “Osterizer 16-spe”
45 g of peeled potatoes having a size of about 3 to 5 cm each adjusted to a water content of 8 to 22% in a constant humidity container using "ed" were crushed for 4 minutes.

The pulverized sample was dried at 105 ° C. for 4 hours, sieved with 100 mesh, and the weight% of the sample passing through 100 mesh was calculated. The relationship between the water content (%) of the peeled and dried potatoes and the 100 mesh pass (%) is as shown in FIG. 2, when the sample water content exceeds 16%.
The ratio that can be pulverized to the target particle size of 150 μm or less greatly decreases, and if it exceeds 17%, the ratio that does not reach the target particle size is 1
The sample moisture content is increased by 16% because it increases by 0% or more.
When the pulverization is performed in the following manner, the pulverizable ratio reaches 78% (about 35 g / batch) up to 150 μm or less, and the pulverization efficiency is good, and a high-concentration slurry can be charged.

Experimental Example 3 shows the enzyme treatment effect when cellulase treatment was performed before liquefaction when suspending dried cassava potato powder in water.

EXPERIMENTAL EXAMPLE 3 A solution prepared by dissolving 0.3 g of cellulase "CELLULASE YC" in 7.2 ml of water was used in Example 1.
5 g of cassava potato powder (water content: about 5%) of a 00 mesh pass was added little by little while stirring. After the total amount was added, the mixture was reacted at 50 ° C. for 2 hours while further shaking and stirring. After adding 7 ml of water, the liquefaction enzyme “T-
5) 0.02 ml (20 units / g of powder) was added, and 9
Shaking and stirring was performed at 5 ° C. for 1 hour. After cooling to room temperature, the pH was adjusted to 4.2 with diluted sulfuric acid, and the saccharification enzyme "NC-
"4.2" (3 units / g of powder) was added, heated to 60 ° C., and stirred at the same temperature for 48 hours. The liquid after completion of saccharification was centrifuged, and the saccharification rate and residue ratio of the saccharified liquid were analyzed. For comparison, Table 3 also shows the results obtained when the same operation was performed without using cellulase.

[0035]

[Table 3]

From the results shown in Table 3, it can be seen that the cellulase treatment prior to liquefaction has a higher saccharification rate and a lower residue rate than the cellulase untreated section. Therefore, it can be said that the cellulase treatment of the powdered cassava is effective in improving the efficiency and the quality of the sugar solution in the saccharification performed thereafter.

Even if the cellulase has a concentration of about 10 FPA (unit / ml), by adding the powder little by little, the fluidity can be maintained up to a high concentration (50 g / dl). Liquefaction / saccharification is smooth and gives a high concentration of sugar solution.

Experimental Example 4 shows the effect of the liquefied enzyme when the liquefied enzyme was added in advance when the dried cassava potato powder was suspended in water.

Experimental Example 4 A solution obtained by adding a predetermined amount of liquefying enzyme "T-5" to 4 ml of water was kept at 40 ° C., and 6 g of powdered cassava potato (moisture content: about 5%) with a 100 mesh pass was gradually added thereto. The total volume was 10 ml, and the slurry was liquefied and saccharified under the same conditions as in Experimental Example 1. The amount of liquefied enzyme to be added is set to 100 units / g, which is a standard amount with respect to the amount of starch, a double amount thereof, and no addition. The enzyme was added.

At the time of powder suspension, there was no difference in the ease of suspension depending on the amount of the enzyme. However, when the temperature was increased and then liquefaction was carried out, the liquefaction proceeded more quickly if the enzyme had been added in advance. The liquid became completely smooth in 30 minutes, which is half of the liquefaction reaction time. At that time, the sample to which the enzyme had not been previously added was not liquefied. Table 4 shows the residue ratio and saccharification ratio when each enzyme amount was added.

[0041]

[Table 4]

From the results shown in Table 4, it can be seen that there is a significant difference in the residue ratio and the saccharification ratio in the group to which the enzyme was added in advance compared to the group without addition of the enzyme, indicating that liquefaction and saccharification can be performed efficiently.

Also, 55 g of powdered cassava potato is gradually added to make a total volume of 100 ml. The set temperature at the time of powder suspension is 40 ° C. before liquefaction, 60 ° C. immediately before gelatinization, and 80 ° C. having high liquefying enzyme activity. Liquefaction and saccharification were performed under the same conditions as in Experimental Example 1 except that the temperature was changed to ° C. Table 5 shows the results.

[0044]

[Table 5]

There is no great difference in the sugar solution concentration. In comparison with the temperature at the time of suspension under the same conditions, the result of the best saccharification rate was 60 ° C, but the smoothness of the suspension was the best at 40 ° C. At 80 ° C., an increase in viscosity was observed, and there was much adhesion to the wall surface of the reaction vessel.

The present invention is further characterized in that the sugar solution of dried cassava potato thus obtained is used as a raw material for amino acid fermentation.

The type of amino acid fermentation is not limited. For example, glutamic acid, lysine, methionine, tryptophan,
Threonine, serine, proline, alanine, valine, leucine, phenylalanine, histidine, arginine,
Fermentation of amino acids such as ornithine, glutamine and aspartic acid can be mentioned as an example.

As the microorganism used for these fermentations, those known for each fermentation can be used. An example is as follows. L-glutamic acid fermentation: Brevibacterium lactofermentum ATCC 13869 L-lysine fermentation: Brevibacterium lactofermentum ATCC 21800 L-tryptophan fermentation: Escherichia coli AGX1
7 (PGX44) [NRRL B-12263] L-phenylalanine fermentation: Brevibacterium lactofermentum AJ12637 (FERM BP-4)
160) French Patent Application Publication No. 2,686,898
See L-Tyrosine fermentation: Brevibacterium lactofermentum AJ12081 (FERM P-7249)
See JP-A-60-70093. L-threonine fermentation: Corynebacterium acetoacidophilum AJ12318 (FERM BP-117)
2) See US Pat. No. 5,188,945 L-isoleucine fermentation: Brevibacterium flavum AJ12149 (FERM BP-759) See US Pat. No. 4,656,135.

The medium used for fermentation may be the same as a known medium except that the sugar solution of the present invention is used as a carbon source. The above sugar solution may be used for the entire amount of the carbon source, or may be used for a part thereof. The remaining carbon source when used for one part may be the same as that used conventionally.

The fermentation method may be the same as the conventional one. However, when the sugar solution of the present invention is used, the growth rate of the bacteria is increased, and the fermentation time can be shortened by about 1 to 5 hours as compared with the conventional method using glucose as a raw material for fermentation.

The concentration of each amino acid obtained by fermentation and the yield to sugar are also almost the same as those of the conventional method.

The fermented liquor contains minute solids and the like derived from cassava syrup obtained by saccharifying the cassava potato as it is, but has little effect on the separation and purification of the target amino acid from the fermented liquor. However, when the cells are subjected to membrane filtration, the filtration rate may decrease depending on the type of the fermenting bacteria and the degree of pulverization of the cassava potato. In that case, means such as centrifugation of the cells may be employed. In the case of amino acids such as lysine, the main use is feed. Therefore, when lysine or the like is used for the feed, the fermented liquid can be dried as it is to obtain a feed additive.

[0053]

EXAMPLES Sugar solution production example 1 Cassava potato powder (moisture content 5%) of 100 mesh pass
About 450 g of water was suspended in water and adjusted to a total volume of 1 L. This was heated to 85 ° C. with stirring, 1.5 ml of liquefied enzyme “T-5” was added, and a liquefaction reaction was performed for 1 hour. After the completion of liquefaction, when the temperature was cooled to 60 ° C., the pH was adjusted to 4.5 with dilute sulfuric acid, and 0.5 ml of saccharifying enzyme “NC-4.2” was added. The saccharification reaction was performed by shaking at 60 ° C. for 48 hours. The glucose concentration in the sugar solution is 3
It was 7.5 g / dl (saccharification rate 90%).

Comparative Example of Sugar Solution Production Liquefaction / saccharification was carried out in the same manner as in Sugar Solution Production Example 1, except that dried cassava potato powder having a water content of 20% (52% in a 100 mesh pass) was used. Where
The glucose concentration in the sugar solution was 34.6 g / dl (saccharification rate 8
3%).

Sugar solution production example 2 40 g of cellulase "CELLULASE YC" was added to water 1
The solution, which was stirred and dissolved in 0 L, was heated to 40 ° C., and stirred with a 100-mesh pass cassava potato powder (starch content 89%).
%) Was added little by little over 1 hour. After adding the whole amount of cassava potato powder, the mixture was reacted at 50 ° C. for 2 hours while stirring.

33.3 ml of the liquefying enzyme "T-5" was added, and the mixture was shaken and stirred at 90 ° C. for 1 hour. The mixture was allowed to cool to 60 ° C., the pH was adjusted to 4.2 with dilute sulfuric acid, 11.3 ml of saccharifying enzyme “NC-4.2” was added, heated to 60 ° C., and stirred at the same temperature for 48 hours. did. After cooling to room temperature, 18.5 L of a sugar solution was obtained. The glucose concentration in this sugar solution is 44
g / dl (saccharification rate 87%).

Sugar Liquid Production Example 3 A solution prepared by stirring and dissolving 133 ml of the liquefying enzyme "T-5" in 20 L of water was heated to 40 ° C., and 17 kg of cassava potato powder (starch content: 74%) of a 100 mesh pass was stirred under stirring. 1
It was added in small portions over time. Stirring was performed at 90 ° C. for 1 hour. Cool to room temperature and adjust the pH to 4.2 with dilute sulfuric acid.
, And 20 ml of saccharifying enzyme "NC-4.2" was added, heated to 60 ° C, and stirred at the same temperature for 48 hours. After cooling to room temperature, 37.5 L of a sugar solution was obtained. The glucose concentration in this sugar solution was 35 g / dl (saccharification rate 97%).

Fermentation Example 1 The culture medium contained glucose 60 g / L and MgSO ₄ 1 g /
_{L, KH 2 PO 4 1g /} L, soybean protein acid hydrolyzate 15ml
/ L, substrate solution containing biotin 300 μg / L 270 m
1 was heat-sterilized at 120 ° C. for 15 minutes and placed in an S-shaped jar.

The glutamate-producing bacterium Brevibacterium lactofermentum (AT
CC 13869) and a total volume of 30 ml.
The volume was 0 ml, and the fermentation was started. Fermentation is 1 to 1.2 krp
m and agitation at 1/1 vvm, and the pH was maintained at 7.5 with ammonia. The fermentation temperature was set at 30 ° C., and 5 hours after the start of the culture, polyoxyethylene sorbitan monopalmitate was added to a concentration of 2000 mg / L.

The sugar solution was prepared by adding glucose to the sugar solution (cassava sugar solution 1) obtained in the sugar solution production example 1 to a glucose concentration of 40 g / dl, and a glucose concentration of 40 g prepared using commercially available glucose. / Dl solution (glucose solution) was used after heat sterilization at 120 ° C for 15 minutes. As the sugar solution, the above-mentioned cassava sugar solution, glucose solution, and a solution obtained by mixing both at a ratio of 1: 1 are used. Polyoxyethylene sorbitan monopalmitate is added at a concentration of 2000 mg / L, and the sugar concentration in the fermentation solution is used as a substrate solution. 1-2 g
/ Dl. As a result of the fermentation, the yield when the glucose substrate solution was continuously supplied was 56%, whereas the 50% cassava substrate was 56% and the 100% cassava substrate was 57%. The culturing time was 3.7 hours for 50% cassava substrate and 100% for glucose substrate.
The cassava substrate was shortened by 4.2 hours.

When each of the fermented liquors obtained above was subjected to membrane separation using a commercially available hollow fiber pencil type membrane module, no remarkable difference in membrane permeability was observed. Further, hydrochloric acid was added to each membrane permeate to adjust the pH to 3.2, and glutamic acid crystals were separated by crystallization.

Fermentation Example 2 A glutamic acid fermentation test was carried out in a 50 L jar using the sugar solution (cassava sugar solution 2) prepared in the sugar solution production example 2. The fermentation was performed under the same conditions as in Fermentation Example 1 except that the liquid volume of the seed culture solution was 2.8 liters, the liquid volume at the start of fermentation was 20 liters, stirring was 250 rpm, and the glucose concentration of the sugar solution was 44 g / dl. went. The result of fermentation was 50% when the glucose substrate was supplied, and the same yield when the cassava substrate was supplied. The culture time was reduced by about one hour.

[0063] Fermentation Example 3 Glucose 30 g / L, ammonium chloride 10 g / L, urea _{3g / L, KH 2 PO 4} 1g / L, MgSO 4 · 7H 2 O
_{100mg / L, FeSO 4 · 7H} 2 O10mg / L,
_{MnSO 4 · 4H 2 O8mg / L} , soybean protein acid hydrolyzate (as nitrogen) 1 g / L, thiamine hydrochloride 0.1mg
/ L and a medium containing 0.3 mg / L of biotin (pH
7.0) was added to each of three 500 ml shake flasks.
Dispensed by mL. After heat sterilization at 115 ° C. for 10 minutes, this medium was mixed with Brevibacterium lactofermentum (ATC) which had been grown on bouillon slant for 48 hours.
C21800) was inoculated with one platinum loop and shake-cultured at 31.5 ° C. for 24 hours. The above is a seed culture. 8 as molasses
0 g / L, ammonium sulfate 50 g / L, KH ₂ PO ₄ 1 g
/ L, MgSO ₄ .7H ₂ O ₁ g / L, soybean protein hydrolyzate (as nitrogen) 100 mg / L, thiamine hydrochloride 0.1 mg / L, and biotin 0.3 mg / L (pH 7.0) Was dispensed into three 1-L small glass fermenters in 300 mL increments and sterilized by heating at 120 ° C. for 15 minutes. After cooling to 31.5 ° C., the above-mentioned flask culture termination solution was added in 15 mL portions per fermenter, and the temperature was adjusted to 3 ° C.
The culture was performed under the conditions of 1.5 ° C., an aeration rate of 1/2 vvm, and a stirring speed of 700 rpm. Feeding of the feed medium was started when the sugar concentration in the culture solution became 5 g / L or less.
The medium was glucose (40 g / dL) or a sugar solution prepared by adding glucose to the sugar solution obtained in the sugar solution production example 3 to adjust the glucose concentration to 40 g / dL, a soybean protein hydrolyzate (100 mg / nitrogen). L), thiamine hydrochloride (0.1 mg / L) and biotin (0.3 mg / L
L). In each case, the sugar concentration in the culture solution was 5 g
The culture is continued while controlling the feed rate of the feed medium so as to be not more than / L. After the feed of 100 mL of the feed medium is completed, the culture is terminated when the sugar in the culture medium is consumed, and the culture medium is stopped. The L-lysine concentration accumulated therein was quantified. As a result of the culture of the two plants, the yield in the case of the glucose feed was 35%, while the yield in the case of the cassava feed was 38%.

Fermentation Example 4 A lysine fermentation test was performed using cassava sugar solution 3 in a 50 L jar. The fermentation was performed under the same conditions as in Fermentation Example 3 except that the liquid volume of the seed culture was 2.75 l, the liquid volume at the start of fermentation was 18 l, the stirring was 250 rpm, and the aeration was 1/2 vvm. The fermentation results show a yield of 34 for glucose feed.
%, While the yield in the case of cassava feed was 37%.

[0065]

As described above, according to the present invention,
By bypassing the starch extraction step, by peeling and drying the dried cassava potato and directly liquefying and saccharifying the enzyme, more than 80% of the starch contained in the powder is saccharified and 40% available as a fermentation feed solution. The high-concentration sugar solution described above can be efficiently produced, and amino acids can be obtained in a short time and with high yield using this sugar solution. Further, according to the present invention, most of cassava starch can be used for saccharification and also for amino acid fermentation, and the amount of waste can be reduced.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing an example of producing starch and scum from cassava potatoes.

FIG. 2 is a graph showing the relationship between the water content (%) of peeled and dried cassava potato and the weight ratio (%) of powder having a particle size of 150 μm or less.

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[Procedure amendment]

[Submission date] May 11, 2001 (2001.5.1
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

As a result of examining the relationship between the particle size, the saccharification ratio and the residue ratio, as shown in Table 2, saccharification is smoother as the particle size is smaller, and 82% of the powder is obtained by pulverizing to a particle size of 150 μm or less. Glucose is obtained and 9 of the starch content
It can be seen that 4% was saccharified.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (5)

[Claims] 1. Peeled and dried to a moisture content of 16% by weight
The dried cassava potato as described below is pulverized to 150 μm or less and suspended in water to prepare a crude starch slurry containing 35% by weight or more of starch. A method for producing a high-concentration sugar solution characterized by saccharification. 2. Peeling and drying to give a water content of 16% by weight
The dried cassava potato was ground to 150 μm or less, suspended in an aqueous solution containing cellulase, and subjected to enzymatic treatment with cellulase to prepare a crude starch slurry containing 35% by weight or more of starch. A method for producing a high-concentration sugar solution, which comprises liquefying an enzyme and saccharifying the enzyme by reacting a saccharifying enzyme. 3. Peeled and dried to obtain a water content of 16% by weight.
The dried cassava potato as described below is pulverized to 150 μm or less, suspended in an aqueous solution containing starch liquefying enzyme, and then 35% by weight.
A method for producing a high-concentration sugar solution, which comprises liquefying an enzyme while preparing a crude starch slurry containing the above-mentioned starch, and then saccharifying the enzyme by the action of a saccharifying enzyme. 4. The method for producing a high-concentration sugar solution according to claim 1, wherein the water content of the dried cassava potato is 5 to 10% by weight. 5. A method for fermentative production of amino acids, comprising using a high-concentration sugar solution produced by the method according to claim 1 as a fermentation raw material.