JPH0640823B2 - Method for producing purified α-amylase-containing liquid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for purifying an enzyme, and particularly to a method with low purity,
Alternatively, the present invention relates to a method for producing a purified α-amylase-containing concentrated liquid, which is suitable for starch liquefaction from a dilute α-amylase-containing solution, has high purity, and has high storage stability.

[Conventional technology]

Currently, glucose and isomerized sugar are industrially produced by hydrolyzing starch with α-amylase and glucoamylase. As described above, polymer hydrolases such as amylase and protease are extremely useful for industrially producing useful low-molecular substances from natural polymer raw materials.

Generally, an enzyme is produced by liquid-culturing an enzyme-producing bacterium.
As an industrial enzyme preparation, generally, a concentrated solution obtained by concentrating the culture solution as it is, a culture solution or a powder obtained by directly drying the culture solution, or a concentrate solution obtained by partial purification,
Alternatively, its dry powder is used. However, concentrated liquids and roughly dried products of the culture broth contain large amounts of odorous and odorous components contained in the culture broth, so when the reaction product of interest is separated and purified, it is finally removed. It becomes necessary to do. Further, the culture solution often contains a protease that destroys the target enzyme.

In particular, when a bacterium is cultured and produced by using a bacterium as an enzyme-producing bacterium, a protease is often produced as a by-product. Therefore, it is necessary to remove these detrimental impurities when the useful substance is produced by utilizing the enzymatic reaction.

The purification of the enzyme is generally carried out by a complicated process in which various physical and chemical methods such as molecular sieve, ion exchange chromatography, salt folding, and pH precipitation are combined, which requires extremely great labor, time and cost.

On the other hand, it has long been known that α-amylase is selectively adsorbed to the substrate starch, and a method of adsorbing α-amylase to the starch particles and then desorbing it has also been reported. However, at the time of desorption, a salt solution, an acid or an alkali solution is used as a desorption solution, and it is necessary to remove the salt, acid or alkali as a post-treatment. Since the enzyme in these purified solutions is extremely dilute in weight concentration, it is difficult to dry due to many losses in the usual industrial method. Further, an aqueous solution of the purified enzyme is inactivated not only at room temperature but also when stored in a cold place, or is inactivated by the growth of microorganisms, so that it cannot withstand long-term storage and is not practical. On the other hand, in order to solve these instabilities, it is possible to dry the starch cake to which α-amylase is adsorbed and use it as an enzyme.

[Problems to be solved by the invention]

However, this α-amylase-adsorbed starch is used as α-amylase in a liquefaction reaction of starch paste solution, that is, glucose, maltose, a pre-process when producing isomerized sugar from starch as a raw material,
The starch starch paste liquid as a raw material liquefies into dextrin, but the starch powder used as an adsorbent does not liquefy, but the dissolved but undegraded starch molecules and starch particles I found that it would remain in the state of. It was found that even if a wet cake before drying was used as the α-amylase-adsorbed starch, it was similarly difficult to decompose. Therefore, the undecomposed dissolved or undissolved starch must be separated and removed before being sent to the saccharification reaction, or must be separated and removed from the target sugar product after the saccharification reaction.

An object of the present invention is to provide a method for producing a stable aqueous enzyme solution by efficiently separating and concentrating the enzyme from a low-purity or dilute solution containing α-amylase.

[Means for solving problems]

Briefly describing the present invention, the present invention is an invention relating to a method for producing a purified α-amylase-containing liquid, in which a crude α-amylase-containing solution is heated at a temperature above the freezing point but substantially no liquefaction reaction of starch is caused. And a step of adsorbing α-amylase to the starch particles, separating the starch particles having adsorbed the α-amylase, and containing α-amylase obtained from the separated starch particles. Each step of treating the liquid with an enzyme containing at least one of glucoamylase and β-amylase to hydrolyze to a sugar having a molecular weight equal to or lower than that of an oligosaccharide is included.

Hereinafter, the present invention will be described in more detail.

The α-amylase that can be used in the method of the present invention is not particularly limited. That is, α-amylases of various origins such as bacteria and filamentous fungi are used. Therefore, room temperature α-amylase,
And a heat-resistant α-amylase may be used, but a heat-resistant α-amylase is particularly useful. Therefore, examples of the crude α-amylase-containing solution, which is the raw material of the method of the present invention, include a liquid obtained by removing solids from a liquid culture of α-amylase-producing bacteria, and extraction from a solid culture or cultured cells. , An extract obtained by removing solid matter can be mentioned.

Adsorption of the α-amylase in the raw material as described above to the starch particles and separation of the adsorbed starch particles can be carried out by the known conventional method described above.

The α-amylase-starch complex thus obtained may be washed with water at a temperature at which the starch liquefaction does not substantially occur before the next treatment, and it is preferable to do so. Is.

Next, there are several methods described below as the method for causing the glucoamylase- or β-amylase-containing enzyme to act.

(1) The above-mentioned complex (that is, one that has been previously washed with water or one that has not been washed with water; the same applies hereinafter) is made into an aqueous slurry, and an enzyme is allowed to act on it.

(2) In the method of (1) above, the enzyme is allowed to act in the presence of starch.

(3) The starch is allowed to act in advance on the aqueous slurry of the complex to make the iodine starch reaction negative, and then the enzyme is allowed to act.

(4) Heat the aqueous slurry of the complex to make the iodine starch reaction negative, and then act the enzyme in the presence or absence of starch.

(5) An aqueous slurry of the complex is heat-treated, and a substance having a negative iodine starch reaction is treated with starch to form dextrin, and the enzyme is allowed to act on the dextrin. In any of the methods, the starch in the complex and the starch added as necessary were both liquefied and further hydrolyzed to sugars having a molecular weight of oligosaccharide or less, and the starch and high starch of the present invention were obtained. A purified α-amylase-containing liquid, free of molecular dextrin, is produced.

The enzyme used may contain at least one of glucoamylase and β-amylase. Therefore,
Both enzymes may be used in combination, simultaneously or in separate steps over time. Still another enzyme may be used simultaneously or in combination in a separate step over time.

Examples of other enzymes that may be used in combination include .alpha.-amylase, as well as bruranase and glucose isomerase.

Further, the slurry in the reaction is preferably one containing 30 to 50% by weight of starch. This is because if it is less than 30% by weight, the reaction with the enzyme tends to be insufficient, while if it exceeds 50% by weight, the viscosity becomes high and the operability is deteriorated.

The source enzyme and its form are not particularly limited.

The α-amylase-containing liquid obtained by the method of the present invention is
It is an extremely highly stable solution in which the α-amylase activity does not decrease even after storage at room temperature for 10 days, and the proliferation of microorganisms is not observed.

Using the enzyme solution according to the present invention, starch starch paste is liquefied and further saccharified, but undegraded starch and high-molecular-weight dextrin are not mixed in each sugar product solution. Is extremely effective for the treatment of.

Further, the enzyme solution according to the present invention does not contain an unpleasant odorous or coloring component and does not contaminate the sugar product with these impurities, so that it can be used as it is or concentrated to obtain a product.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these examples.

In addition,% in each example is weight / weight unless otherwise specified.

Example 1 Soluble starch 1.6%, polypeptone 0.6%, yeast extract 0.5%, potassium phosphate first 0.7%, phosphate second
Liquid medium (pH 6.0) containing 0.35% sodium, 0.001% magnesium sulfate heptahydrate and tap water,
Dispense 1.52 kg into a culture tank with an internal volume of 5 and
Sterilize for 0 minutes. A thermostable α-amylase-producing bacterium [Clostridium genus bacterium RS-0001, Microtechnology, Inc.
No. 043 (FERM BP-1043)] was added. Then, after replacing the gas phase portion of the culture tank with argon gas,
Cultured under anaerobic conditions. The culture was carried out for 46 hours while automatically adjusting the pH in the culture tank to 6.0 and the temperature to 60 ° C. This culture solution was centrifuged at 6000 rpm for 10 minutes to remove the cells, and a culture solution 1.5 having an α-amylase activity of 4.8 units / ml was obtained. Inorganic salt 1.1%, α-
Contains 2.3% of organic substances other than amylase. The specific activity of the main culture solution per solid content was 98.2 units / g.

In particular, since the organic substance contains about 0.3% of volatile fatty acids containing acetic acid and propionic acid as main components, it has an unpleasant acid odor and sulfide odor.

Next, 0.5 of the main culture broth (containing 2,100 units of α-amylase, pH 6.0) was cooled to 5 ° C.
25 g of starch slurry in which 0 g and 15 g of water were mixed was added, and the mixture was kept under stirring for 1 minute. The above liquid was centrifuged (3,000 rpm, 5 minutes) to obtain 25 g of a slurry of α-amylase / starch complex and 0.5 of a clear liquid. As a result of measuring the α-amylase activity of the above clarified liquid,
It was estimated that 90% of α-amylase was recovered as α-amylase-starch complex.

25 g of the slurry of the above α-amylase-starch complex was reacted at 60 ° C. for 1 hour. As a result, the reaction solution was negative in the iodine starch reaction, and it was confirmed that the liquefaction reaction proceeded sufficiently. Moreover, as a result of measuring the total activity of α-amylase in the reaction solution, it was 1856 units, and it was understood that 88% of the α-amylase contained in the culture solution remained. In addition, this solution has a slight acid odor and has a pale yellow color. The specific activity per volume of this solution was 74.2 units / ml, which was concentrated 15.5 times per volume. This liquid has a specific activity on a dry matter basis of components other than sugar of 5.46 × 10 ³ units /
g, which is 57 times as purified as the culture solution.

30% of 5 ml of this solution (containing 371 units of α-amylase)
It was added to 1000 g of potato shiyo starch powder slurry which had been heat-treated at 100 ° C. for 10 minutes, and heated under stirring at 70 ° C. for 1 hour. As a result, the reaction solution showed a negative iodine starch reaction, and the following formula: Dextrose Equivale
nt) 1005 g of a dextrin solution with a DE of 12 were obtained.

The dextrin solution is colorless, and when heated to 50 ° C. or higher, a slight acid odor derived from the culture solution is felt, but it is a colorless and odorless transparent liquid at room temperature.

In 100 g of the above dextrin solution, glucoamylase [Aspergillus niger origin, room temperature] (Novo Industry Co., Ltd., trade name amyloglucosidase novo AMG-200L, the following Examples and Comparative Examples of the present specification) All the glucoamylases used in () mean this) 200 units (0.1 g) of purified powder obtained by encapsulating the liquid in a cellophane semipermeable membrane tube, dialyzing against distilled water, and freeze-drying. Add and dissolve, 50
The dextrin was hydrolyzed to glucose by incubating at 48 ° C for 48 hours. The glucose concentration after the reaction reached 96.5%.
This liquid is a transparent liquid without odor or color derived from the culture liquid.

Using this solution as a purified amylase solution, the storage stability at low temperature and room temperature was tested. This solution was stored at 2 ° C. and 25 ° C. for 10 days and 6 months, and its enzyme activity was measured. As a result, when stored at 2 ° C, 99% or more even at 6 months storage, 25 ° C,
It was confirmed that 98% or more of the activity was retained after 6 months storage.

Further, 1 ml of this solution (containing 7.4 units of α-amylase) was added to 200 g of 30% potato starch starch slurry as a purified α-amylase-containing solution, and heated at 70 ° C. for 1 hour. As a result, the reaction solution showed a negative iodine starch reaction,
About 200 g of a dextrin solution having a DE of 12.5 was obtained.
The dextrin solution is a colorless and transparent liquid without unpleasant odor derived from the culture solution.

Example 2 Culture was carried out in the same manner as in Example 1 to obtain 14 per solid content of the culture solution.
A culture broth having a specific activity of 2 units / g was obtained.

Next, this culture solution is reacted with potato starch and starch in the same manner as in Example 1 to prepare a slurry 2 of α-amylase / starch complex.
5 g and clear liquid 0.5 g were obtained.

25 g of the above slurry, 100 ml of distilled water (5 ° C, pH 6.2)
After adding and mixing, centrifuge (3000 rpm, 5 minutes)
Then, washed composite slurry 30g and cleaning waste liquid 95ml
Got As a result of measuring the α-amylase activity of the clarified liquid and the washing waste liquid, the α-amylase activity that was not adsorbed on the starch was 102 units or less. Therefore,
It was estimated that 95% of α-amylase in the test culture solution was recovered as α-amylase-starch complex.

30 g of the slurry of the above α-amylase / starch complex was reacted at 60 ° C. for 1 hour. As a result, the reaction solution was negative in the iodine starch reaction, and it was confirmed that the liquefaction reaction proceeded sufficiently. Moreover, as a result of measuring the total activity of α-amylase in the reaction solution, it was found that it was 1990 units, and that 95% of α-amylase contained in the culture solution remained. The liquid was almost colorless and transparent and had no odor, and the inorganic salt concentration was 0.01% or less. The specific activity of this solution per volume was 74.2 units / ml, which was concentrated 15.5 times per volume. Furthermore, this liquid has a specific activity on a dry matter basis of components other than sugars of 1.92 × 10 ⁴ units / g, and is purified 135 times that of the culture liquid.

30% of 5 ml of this solution (containing 322 units of α-amylase)
Add to 1000g of horse-chilled starch powder slurry and add 1 at 70 ℃
After heating for an hour, the iodine starch reaction was negative and the DE was 1
1005 g of the dextrin solution of 2 was obtained.

This dextrin solution is a transparent liquid that has no odor or color derived from the culture solution.

Purified powder of glucoamylase (originating from Aspergillus niger, room temperature) 180 g in 100 g of the above dextrin solution
A unit (0.09 g) was added and dissolved, and the mixture was kept at 50 ° C. for 48 hours to hydrolyze dextrin into glucose. The glucose concentration after the reaction reached 96.6%. This glucose solution is a transparent liquid without odor or color derived from the culture solution.

In addition, 1 ml of this liquid (containing 6.4 units of α-amylase) was added as a purified α-amylase solution to 200 g of 30% horse-cooled starch starch slurry at 100 ° C for 10 minutes, 70 ° C, Heated for 1 hour. As a result, the reaction solution showed a negative iodine starch reaction, and about 200 g of a dextrin solution having a DE of 12.4 was obtained. This dextrin solution is a colorless and transparent liquid without any unpleasant odor derived from the culture solution.

The storability of the above purified amylase solution was tested.
This solution was stored at 2 ° C. and 25 ° C. for 10 days and 6 months, and its enzyme activity was measured. As a result, 99% or more was stored at 2 ° C for 6 months and 9% at 25 ° C for 6 months.
It was confirmed that the activity was maintained at 9% or more.

Example 3 To 100 g of the dextrin solution obtained in Example 2, 500 units (0.2 g) of purified powder of β-amylase (malt origin, room temperature) was added and dissolved, and the mixture was kept at 45 ° C. for 48 hours to give dextrin. It was hydrolyzed to a mixture of maltose and a small amount of maltotriose and glucose. The maltose concentration after the reaction reached 93%. This maltose liquid is a transparent liquid without odor or color derived from the culture liquid.

Using this solution as a purified amylase solution, the storage stability at low temperature and room temperature was tested. This solution was stored at 2 ° C. and 25 ° C. for 10 days and 6 months, and its enzyme activity was measured. As a result, it was confirmed that 98% or more of the activity was retained even after 6 months storage at 2 ° C and 25 ° C.

In addition, 1 ml of this liquid (containing 6.4 units of α-amylase) was added as a purified amylase solution to 200 g of 30% potato starch starch slurry at 100 ° C for 10 minutes, and 70 ° C for 1 hour. Heated. As a result, the reaction solution showed a negative iodine starch reaction, and about 200 g of a dextrin solution having a DE of 12.2 was obtained. This dextrin solution is a colorless and transparent liquid without any unpleasant odor derived from the culture solution.

Example 4 Culture was carried out in the same manner as in Example 1 to obtain 8 per solid content of the culture solution.
A culture solution having a specific activity of 9.0 units / g was obtained.

Then, the same treatment as in Example 2 was performed to obtain a clarified liquid, a composite slurry, and a cleaning waste liquid. Clearing liquid and washing waste liquid α
-As a result of measuring amylase activity, the amount of α-amylase activity not adsorbed on starch was 100 units or less. Therefore, 95.8% of α-amylase in the test culture solution was
-It was estimated that it was recovered as an amylase-starch complex.

To 25 g of the above-mentioned α-amylase-starch complex slurry, 50 units (0.05 g) of purified powder of glucoamylase (originating from Aspergillus niger, room temperature) was added and dissolved, and 5
The mixture was incubated at 5 ° C. for 48 hours, and the starch of the α-amylase / starch complex was simultaneously liquefied and saccharified by the α-amylase contained in the complex and the added glucoamylase. As a result, the reaction solution showed a negative iodine starch reaction,
Α-amylase containing 95% glucose in the sugar composition,
A purified enzyme solution containing glucoamylase was obtained. This enzyme solution was almost colorless and transparent and had no odor, and the specific activity of α-amylase per volume of this solution was 90 units / ml, and was 18.
It was concentrated 9 times. Total activity recovered at this time is 225
It was 0 unit, and it was understood that 97.8% of the α-amylase activity contained in the culture solution remained. Furthermore, the specific activity of the components excluding sugar and glucoamylase per dry matter was 1.8 × 10 ⁴ units / g, which means that it was purified 183 times as much as the main culture solution.

1 ml of the above purified enzyme solution (containing 90 units of α-amylase)
Was added as a purified α-amylase solution to 200 g of 30% potato starch powder slurry which had been heat-treated at 100 ° C for 10 minutes, and heated at 70 ° C for 1 hour. As a result, the reaction solution showed a negative iodine starch reaction, and about 200 g of a sugar solution having a DE of 12.6 was obtained. This sugar solution is a colorless and transparent liquid with no unpleasant odor derived from the culture solution.

The storability of the above purified amylase solution was tested.
This solution was stored at 2 ° C. and 25 ° C. for 6 months, and its enzyme activity was measured. As a result, it was confirmed that 98% or more of the activity was retained at 6 ° C storage at 2 ° C and 99% or more at 25 ° C.

Example 5 Culture was carried out in the same manner as in Example 1 to obtain 5.1 units / ml of α-amylase activity, and 102 units / g of solid content of the culture solution.
A culture solution having a specific activity of was obtained.

Then, the same treatment as in Example 2 was performed. As a result of measuring the α-amylase activity of the clarified liquid and the washing waste liquid, the α-amylase activity which was not adsorbed on the starch was 102 units or less.
Therefore, it was estimated that 96% of α-amylase in the test culture solution was recovered as α-amylase-starch complex.

50 g (0.05 g) of purified powder of glucoamylase (originating from Aspergillus niger, room temperature) and purified powder of vullanase [origin from Bacillus cereus] in 25 g of slurry of the above α-amylase-starch complex. Add 10 units (0.02g) and dissolve, 55 ℃ 48
After keeping the temperature for a while, the starch of the α-amylase-starch complex was simultaneously liquefied and saccharified by the α-amylase contained in the complex and the added glucoamylase and bruranase. As a result, the reaction solution showed a negative iodine starch reaction,
An α-amylase purified enzyme solution containing glucoamylase and pulllawase having a sugar composition of 95% glucose was obtained. The solution was almost colorless and transparent and had no odor. The specific activity of α-amylase per volume of the solution was 96 units / ml, and the solution was concentrated 18.8 times per volume. The total activity of the recovered solution at this time was 2401 units, and it was understood that 98% of the α-amylase activity contained in the culture solution remained.

Furthermore, the specific activity per dry matter of the components excluding sugar, glucoamylase, and pullulanase was 1.9 × 10 ⁴ units / g, which means that it was purified 186 times that of the main culture.

1 ml of the above purified α-amylase solution (α-amylase 96
(Containing unit) was added to 200 g of 30% potato starch powder slurry and heated at 70 ° C. for 1 hour. As a result, the reaction solution showed a negative iodine starch reaction, and about 200 g of a sugar solution having a DE of 12.6 was obtained. This liquid is a colorless and transparent liquid with no unpleasant odor derived from the culture liquid.

The storability of the above purified amylase solution was tested.
This solution was stored at 2 ° C. and 25 ° C. for 6 months, and its enzyme activity was measured. As a result, it was confirmed that 98% or more of the activity was retained at 6 ° C storage at 2 ° C and 99% or more at 25 ° C.

Example 6 Soluble starch 1.5%, polypeptone 0.5%, yeast extract 0.5%, potassium phosphate first 0.7%, phosphate second
Liquid medium (pH 7.0) containing sodium 0.35%, magnesium sulfate heptahydrate 0.001% and tap water was dispensed into 15 Sakaguchi flasks with an internal volume of 500 ml, 100 ml each, at 120 ° C for 15 minutes. Sterilize. To this, Bacillus subtilis (Bacillus subtilis) aerobically cultured in the same medium.
An aerobic culture solution of an α-amylase-producing bacterium belonging to the genus Tilis) was dispensed in 10 ml aliquots and shake-cultured at 37 ° C for 15 hours (120 strokes / minute). This culture solution was centrifuged at 5000 rpm for 15 minutes to remove the cells, and a culture solution 1.5 having an α-amylase activity of 8.1 units / ml was obtained. The main culture liquid contains 1.1% of inorganic salts and 1.2% as organic substances other than α-amylase. Particularly, the organic matter contains about 0.05% of volatile fatty acids containing acetic acid and butyric acid as main components. Therefore, it has an unpleasant acid odor. The specific activity per solid content of the main culture was 352 units / g.

Next, 0.5 of the main culture broth was cooled to 5 ° C., 10 g of potato starch was added thereto, and the mixture was kept under stirring for 1 minute. The above liquid was centrifuged (3,000 rpm, 5 minutes) to obtain 25 g of a slurry of α-amylase / starch complex and a clarification plate 0.5. Distilled water 10 to 25 g of the above slurry
After adding 0 ml (5 ° C., pH 6.2) and mixing, centrifugation (3000 rpm, 5 minutes) was performed to obtain 25 ml of the washed α-amylase-starch complex slurry, and 100 ml of a waste liquid for washing. As a result of measuring the α-amylase activity of the above-mentioned clarified liquid and washing waste liquid, the α-amylase activity which was not adsorbed on starch was 250 units or less in terms of the total culture liquid 1.5. This means that 98% of the α-amylase in the culture solution was recovered as the α-amylase-starch complex.

Next, 100 g of potato shiyo starch of the pharmacopoeia and warm water at 50 ° C 2
To the mixture with 30 ml, 29 g of the above α-amylase / starch complex and 200 units of glucoamylase powder (originating from Aspergillus niger, 0.1 g) were added and reacted at 50 ° C. for 48 hours. Then, 300 units of glucose isomerase powder [Streptomyces genus origin, 0.2 g] was added, and the mixture was reacted at 50 ° C. for 10 hours. The saccharification rate after the reaction (the ratio of the total amount of fructose and glucose to the total solid content in the liquid is expressed in%) was 96%. This high-fructose corn syrup is a clear liquid with no odor or color derived from the culture solution
The inorganic salt concentration is 0.01% or less. The specific activity of α-amylase per volume of this solution was 35.3 units / ml, which was 4.4 times concentrated per volume.

Further, this solution has a dry matter-based α-amylase specific activity of components other than sugar, glucoamylase, and glucose isomerase of 1.5 × 10 ⁴ units / g, which is 42.6 with respect to the culture solution.
It is twice as purified.

The storability of the purified amylase solution was tested. 2 this solution
It was stored at 5 ° C for 10 days, and its enzyme activity was measured. As a result, it was confirmed that the activity was maintained at 85% or more.

Comparative Example 1 The following experiment was conducted as a conventional technique corresponding to Example 1.
That is, α-amylase adsorbed in the culture solution
-The amylase / starch complex is treated with glucoamylase to saccharify the starch particles of the complex to obtain a purified amylase solution containing a high concentration of sugar, which is used for liquefaction and saccharification of starch as compared with Example 1. , Α-amylase-starch complex as α
Used as amylase for liquefaction and saccharification of starch.

Using the same lot culture solution and starch as in Example 1, 25 g of a slurry of α-amylase / starch complex was prepared by the same procedure. 5% of this complex (containing 371 units of α-amylase) was added to a 30% potato starch slurry at 100 ° C., 10 ° C.
Add to heat treated for 1 minute, and stir to 70 ° C under stirring.
Heated for hours. As a result, 1005 g of a DE9.5 dextoin solution containing undecomposed starch particles was obtained as the reaction liquid.
This dextrin solution is semi-transparent because undecomposed starch particles originating from the complex starch particles remain.

Purified powder 200 of glucoamylase (originating from Aspergillus niger, room temperature) in 100 g of the above dextrin solution
A unit (0.1 g) was added and dissolved, and the mixture was incubated at 50 ° C. for 48 hours for saccharification reaction. The glucose concentration after the reaction is 8
It is translucent at 8.1%, containing undegraded starch particles originating from the complex. As a result of analyzing the sugar composition of this sugar solution, it was found that, in addition to glucose, 9.8% oligosaccharide was contained, and 2% of a glycosyl polymer higher than oligosaccharide was contained.

〔The invention's effect〕

As described above, the purified α obtained by the method of the present invention
-The amylase-containing liquid has no odor or coloration, and when it is used for the production of glucose or isomerized sugar, the starch used as an adsorption carrier does not remain undecomposed and is not saccharified or isomerized. This is a remarkable effect that can be realized.

Claims (3)

[Claims] 1. A step of contacting a crude α-amylase-containing solution with starch particles at a temperature above the freezing point but substantially not causing a liquefaction reaction of starch to adsorb α-amylase to the starch particles. A step of separating the starch particles having adsorbed the α-amylase, and treating the α-amylase-containing liquid obtained from the separated starch particles with an enzyme containing at least one of glucoamylase and β-amylase. A method for producing a purified α-amylase-containing solution, comprising the steps of hydrolyzing a sugar having a molecular weight not higher than that of an oligosaccharide. 2. The purified α- according to claim 1, wherein the separated starch particles are washed with water at a temperature at which the liquefaction reaction of starch does not substantially occur, and then the following step is carried out. Method for producing amylase-containing liquid. 3. The crude α-amylase-containing solution is a liquid obtained by removing solids from a liquid culture of α-amylase-producing bacteria, or an extract obtained by extracting from solid cultures or cultured cells to remove solids. A method for producing the purified α-amylase-containing solution according to claim 1 or 2.