JPH07313147A - New microbe and production of protein hydrolyzate - Google Patents

Abstract

PURPOSE:To convert various proteins into the corresponding glutamic acid-rich protein hydrolyzates excellent in gustatoriness by making a protease obtained by culturing specific Xanthomonas microbes act on such proteins. CONSTITUTION:A cultured product or a fractionated product therefrom containing a protease obtained by culturing e.g. Xanthomonas maltophilia AJ12980 (FERM P-14298) having ability to produce the highly active protease is made to act on various proteins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a protein hydrolyzate, an enzyme preparation used for protein hydrolysis, and these methods and a novel microorganism used for producing the enzyme preparation. It is intended to provide a protein hydrolyzate having a high content of glutamic acid, which is important for taste.

[0002]

2. Description of the Related Art Hydrolysates obtained by hydrolyzing soybean proteins and proteins such as wheat contain a large amount of free amino acids and are expected to be used in the food field and the like. Conventionally, a hydrochloric acid decomposition method or an enzymatic decomposition method has been attempted for the production of a protein hydrolyzate. The hydrochloric acid decomposition method is a method of hydrolyzing soybean protein with strong hydrochloric acid, and the decomposition liquid obtained by this method has a decomposition rate (formol nitrogen / total nitrogen) of 70%.
As described above, the release rate of glutamic acid (glutamic acid / total nitrogen) is as high as 1.2 (complete decomposition), and it is extremely excellent in terms of umami.

However, in general, when a protein hydrolyzate is obtained by the hydrochloric acid decomposition method, the reaction condition is 100 ° C.
It takes ~ 2 days, but the reaction at high temperature for a long time consumes a large amount of energy. Further, while hydrolysis of protein with an acid is simple, it has drawbacks such as generation of offensive odor, excessive decomposition of amino acid, and high salt content due to neutralization.

On the other hand, an enzymatic decomposition method, that is, a method of enzymatically decomposing a protein to produce an amino acid solution has been tried for a long time. A protein is a complex substrate for an enzymatic reaction, and a complex enzyme system is required to convert it into an amino acid. Usually, in order to achieve the purpose, a filamentous form centered on Aspergillus oryzae is used. Bacteria are used. Further, in recent years, a production method using a protease such as a protease has been proposed in order to effectively utilize the flavor of the raw material. As described above, as a method for producing a seasoning by enzymatic decomposition of protein, a method for producing an egg white degradation product (JP-A-48-68773) and a method for producing a seasoning liquid obtained from defatted soybean (JP-A-51-70852) , A method for producing a seasoning using cheese whey as a raw material (JP-A-62-151155), a method for producing a corn gluten meal hydrolyzate (Japanese Patent Publication No. 2-295437).
No.) etc. have been reported.

[0005]

However, as seen in the examples of soy sauce brewing, although the enzymatic hydrolysis of the protein requires a great deal of labor and time, the amino acid liberation rate is low, especially in soybean protein. The disadvantage is that the release rate of glutamic acid, which is the most abundant in glutamic acid and which is important for taste, is low.

The present invention has been made from such a viewpoint, and a hydrolase capable of efficiently hydrolyzing a protein, in particular, a microorganism producing the enzyme having a high glutamic acid-releasing rate is obtained, and the enzyme is used. An object is to provide a method for efficiently producing a protein hydrolyzate.

[0007]

[Means for Solving the Problems] The inventors of the present invention obtain a decomposition solution having a high decomposition rate and a high glutamic acid release rate when a culture of a single microorganism is allowed to act on soybean protein as a substrate. If it is possible, it is thought that the above problems can be solved, and when such microorganisms are widely screened from the natural world, it has extremely high protein hydrolyzing ability for a kind of bacteria isolated from soil, Xanthomonas maltophilia, and that it has a significantly high glutamic acid releasing ability. The present invention has been completed and the present invention has been completed.

That is, the present invention is an active ingredient of Xanthomonas maltophilia AJ12980 (FERM P-14298), which produces a proteolytic enzyme having high activity, and a proteolytic enzyme obtained by culturing a microorganism belonging to the genus Xanthomonas. As an enzyme preparation for protein hydrolysis. Further, the present invention is a protein hydrolyzate characterized in that a culture containing a protein hydrolase obtained by culturing a microorganism belonging to the genus Xanthomonas or a fraction thereof is allowed to act on a protein to hydrolyze the protein. To provide a manufacturing method of.

In the present specification, an active ingredient having an activity of hydrolyzing a protein into a peptide and further into a free amino acid is referred to as "proteolytic enzyme" for convenience, but this does not necessarily mean a single enzyme. It is not meant to be one, but is meant to include the case where the active ingredient is a group of plural kinds of enzymes which respectively catalyze a plurality of reactions. In addition, “proteolytic enzyme having high activity” means a proteolytic enzyme having both high proteolytic activity and high glutamate releasing activity.

<1> Microorganism of the present invention Microorganism of the present invention, Xanthomonas maltophilia ( Xa
nthomonas maltophilia ) AJ12980 (FERM P
-14298) uses a casein plate or the like as a medium,
It is a novel microorganism isolated from nature using protease activity as an index, and has the property of producing a hydrolase having high proteolytic activity and glutamic acid releasing activity. The mycological properties are as shown in Example 1 below.

The bacteriological properties of the microorganisms of the present invention are determined by Berge
y's Manual of Determinati
ve Bacterology vol. 1 p18
5-186 (1984), Internationala
l Journal of Systematic Ba
cteriology vol. 23 p333-33
9 (1973), and Identification
Methods in Applied and En
virtual Microbiology
vol. 29 p1 to 19 (1992), the microorganism of the present invention was found to be xanthomonas.
Identified as Martophilia. This strain was named Xanthomonas maltophilia AJ12980, and was founded by FERM in the Institute of Biotechnology, Institute of Biotechnology, Ministry of International Trade and Industry.
It has been deposited with a deposit number of P-14298.

The microorganism of the present invention uses, for example, a casein plate as a medium and uses halo formation due to protease activity as an index, or α-L-glutamyl-p.
By using a medium containing -nitroanilide, α-L-glutamyl-p-nitroanilide is decomposed by a protease, and a halo formed by developing a yellow color is observed, whereby the halo can be separated from the natural world.

<2> Cultivation of a microorganism belonging to the genus Xanthomonas The microorganism belonging to the genus Xanthomonas used in the present invention includes Xanthomonas maltophilia. Xanthomonas maltophilia AJ12980 (a new strain isolated for the first time by the present invention) FERM P-1
4298) is preferred.

A medium used for culturing a microorganism belonging to the genus Xanthomonas to produce a protein hydrolase is
The medium is not particularly limited as long as it can grow Xanthomonas bacteria, but in order to induce a protein hydrolase and stably produce it, a protein such as soybean protein is contained in the medium as a main nitrogen source and carbon source. Is effective.

The medium is preferably a liquid medium, specifically, adipron SU (isolated soybean protein, Ajinomoto Co., Inc.)
Made) 1.5%, casein 1.5%, glucose 7.0
%, Corn steep liquor 1.0%, potassium dihydrogen phosphate 0.25%, magnesium sulfate heptahydrate 0.02
% -Containing medium (pH 7.0) and the like.

The culture conditions include a culture temperature of 20-40.
C is preferable, the optimum temperature is about 30 ° C., and the culture time is usually 12 to 72 hours, preferably 36 to 48.
It's time. The culture is preferably carried out under aerobic conditions while shaking at about 120 rpm.

By culturing the microorganism belonging to the genus Xanthomonas as described above, a culture solution containing a hydrolase can be obtained. This culture solution can be used as it is, but if necessary, it may be further roughly purified to remove medium components and the like, and further purified to enzyme protein. Alternatively, the crude enzyme solution may be freeze-dried and used as a powdery enzyme. The enzyme can be purified by appropriately combining methods commonly used for protein purification, such as salting out, gel filtration and ion exchange chromatography.

<3> Method for Producing Enzyme Preparation for Protein Hydrolysis and Protein Hydrolyzate of the Present Invention The enzyme preparation for protein hydrolysis of the present invention comprises a protein hydrolase obtained by culturing a microorganism belonging to the genus Xanthomonas. Contains as an active ingredient. The enzyme preparation of the present invention includes, in addition to a culture solution or a fraction such as a crudely purified product of protein hydrolase or a purified enzyme, other components usually used in enzyme preparations such as a stabilizer, an excipient, and a pH. You may mix | blend a preparation agent, a filler, a binder, etc. Also, the dosage form is not particularly limited, and a dosage form such as powder, granules, tablets and the like may be selected according to the application.

The method for producing a protein hydrolyzate of the present invention is to hydrolyze a protein by allowing a culture containing a protein hydrolase obtained by culturing a microorganism belonging to the genus Xanthomonas or a fraction thereof to act on the protein. It is characterized by doing. In the present invention, a culture solution of a microorganism belonging to the genus Xanthomonas may be used as it is, or may be used as a crude product of proteolytic enzyme or a fraction of purified enzyme.
Moreover, when the enzyme preparation is prepared as described above, it can be conveniently used for the production of protein hydrolysates.

The type of protein to which the present invention can be applied is not particularly limited, but one having a high glutamic acid content is preferable. Further, the protein raw material is not limited to pure protein, and any protein containing a large amount of protein may be used. Specific examples include defatted soybeans, isolated soybean protein, and the like,
These may be used alone or in appropriate combination of two kinds. Protein raw materials other than these may be used. Also,
The pretreatment of the protein raw material before the enzyme treatment is not particularly limited, but it is preferable that the protein raw material is degreased using a surfactant or an organic solvent.

By reacting such a protein with a culture containing the above-mentioned proteolytic enzyme, a fraction thereof, or an enzyme preparation, the protein is decomposed into peptides and even amino acids by an enzymatic reaction. In order to efficiently carry out the enzymatic reaction, it is preferable that a culture containing a protein hydrolase, a fraction thereof or an enzyme preparation and a protein raw material are allowed to coexist in an aqueous solution. At this time, the reaction may be carried out while stirring.
The enzyme reaction varies depending on the enzyme concentration and protein raw material,
For example, 3 at 10 to 60 ° C, preferably 30 to 50 ° C.
It may be carried out for 10 days, preferably 5-8 days. Also,
The aqueous solution containing the protein hydrolase and the protein raw material is preferably adjusted to pH 5 to 9 using a buffer solution or the like.

After completion of the reaction, insoluble matter such as unreacted raw material protein may be removed by a conventional separation method such as centrifugation or filtration. The produced protein degradation solution may be subjected to amino acid analysis, ninhydrin quantification, and the weight degradation rate by weight comparison before and after the enzyme treatment.

The protein hydrolase used in the present invention is not limited to an enzyme prepared from a microorganism belonging to the genus Xanthomonas, and Escherichia coli, Bacillus subtilis, into which a gene for the enzyme linked to an expression vector has been introduced, It is also possible to use an enzyme produced by a recombinant DNA method such as yeast. In addition, when the protein hydrolase is derived from multiple genes, E. coli, Bacillus subtilis,
It may be introduced into yeast or the like. The enzyme produced by any method can be expected to be as effective as the enzyme obtained from a bacterium of the genus Xanthomonas.

[0024]

[Function] The bacterium of the genus Xanthomonas used in the present invention is
It produces enzymes that are excellent in the ability to decompose various proteins such as defatted soybeans and isolated soybean proteins. Therefore, by using a culture solution containing this enzyme or a fraction thereof, it has low utility value and is not easily degraded by conventional enzymes. Various proteins can be neutrally and mildly hydrolyzed. As a result, a protein hydrolyzate having a high decomposition rate and a high glutamic acid content and excellent taste can be obtained. Further, at the same time, it is possible to solve the problems of disposal of processing by-products and the conventional problems associated with the acid decomposition method. In particular, a novel strain of Xanthomonas maltophilia AJ129 isolated according to the present invention
The proteolytic enzyme contained in the culture solution of 80 (FERM P-14298) has high proteolytic activity and glutamic acid releasing activity.

[0025]

EXAMPLES As examples of the present invention, Xanthomonas maltophilia AJ12980 (FERM P-1) will be described below.
4298) and a method for producing various protein hydrolysates will be described.

[0026]

Example 1 (Xanthomonas maltophilia AJ
Separation of 12980 (FERM P-14298)) According to a conventional method, 2.0% of glucose, 0.5% of casein, 0.02% of phytin, 0.4% of potassium dihydrogenphosphate, 0.4% of disodium hydrogenphosphate from soil. 0.6%, magnesium sulfate heptahydrate, sodium chloride 0.1%, agar 2%
In a casein plate (pH 7.0) containing
About 1300 strains that form a protease halo at ℃
The stock was separated.

Next, each of the separated strains was glucose 7.0%, adipron SU (isolated soybean protein, manufactured by Ajinomoto Co., Inc.) 1.5%, casein 1.5%, corn steep liquor 1.0%. , Potassium dihydrogen phosphate 0.25
%, Magnesium sulfate heptahydrate 0.02% in a medium (pH 7.0) for 48 hours at 30 ℃, the culture solution was α-L-glutamyl-p-nitroanilide 0.02.
5%, casein 0.5%, dipotassium hydrogen phosphate 1.0
%, 8 mm on a medium (pH 7.0) containing 2.0% agar
Spot 0.1 ml on a φ paper disc, 30 ℃
After culturing for 48 hours at 37 ° C, the halo diameter of protease and α-
Observing the L-glutamyl-p-nitroanilide decomposition halo (yellow), the halo diameter of the protease was 20 mm or more,
About 180 positive strains of α-L-glutamyl-p-nitroanilide-degrading halo were used as the second selection bacteria.

Then, the secondary selection bacteria were glucose 7.0.
%, Adipron SU (isolated soy protein, manufactured by Ajinomoto Co., Inc.)
Medium (pH 7.0) containing 1.5%, casein 1.5%, corn steep liquor 1.0%, potassium dihydrogen phosphate 0.25%, and magnesium sulfate heptahydrate 0.02%.
Incubate at 30 ° C for 48 hours at room temperature and add 1 ml of the culture to 5%
Adipron SU (isolated soy protein, Ajinomoto Co., Inc.) 4m
N, which has the highest decomposition rate (formol nitrogen / total nitrogen) and glutamic acid release rate (free glutamic acid amount / total nitrogen) of the decomposed solution.
o. 443 strains were isolated. This bacterium is a novel strain, as described later, and is Xanthomonas maltophilia AJ1.
It is named 2980 and has been deposited with the FERMP-14298 deposit number at the Institute of Biotechnology, Institute of Biotechnology, AIST.

The bacterium can also be isolated by the method described below. Low molecular weight peptides containing proline, hydroxyproline and glycine (particularly di- and tri-peptides) are hardly hydrolyzed by ordinary peptidases. Therefore, screening was performed under the assumption that the bacteria having a peptidase that efficiently decomposes these low-molecular-weight peptides have a highly active peptidase group involved in soybean protein degradation.

According to a conventional method, about 500 strains which grow on a broth agar medium were isolated from the soil. Each of these colonies was inoculated into a 96-well plate containing broth medium and cultured, and the prolidase and carboxypeptidase P activities were measured. As a result, the strain of the present invention showing carboxypeptidase P activity was obtained.

The activity was measured by adding the substrate Z-Pro-Leu to a bacterial suspension (20 mM Tris buffer, pH 7.0).
(Substrate for measuring carboxypeptidase P activity), Leu
-Pro (prolidase activity measurement substrate) at a final concentration of 2.
After adding 5 mM each, the mixture was incubated at 37 ° C. for 6 hours, spotted on a thin layer plate, sprayed with ninhydrin, and confirmed from the color development of leucine and the Rf value.

The mycological properties of this bacterium are shown below.

(A) Presence or absence of morphological properties and motility Cell size and shape: 0.4 to 0.5 × 1.0 to 1.
5 μm bacilli (no polymorphism) Gram stainability: Gram negative Motility: Motile at 30-37 ° C. Flagella characteristics: polar flagella, multiple (1 to 3).

(B) Growth condition on nutrient medium Nutrient agar plate: Growth is moderate. Colony morphology is round, smooth and shiny. Semi-transparent, light tan. When the bacterial cells were suspended in physiological saline (0.9%), the bacterial cell properties were difficult to uniformly disperse.

Nutrient liquid medium: Moderate growth. At the upper edge of the liquid surface of the test tube, an agglutination zone (width ~ 1 mm) of bacteria was formed. The liquid became uniformly cloudy and a viscous precipitate formed (30
C, culture for 2 days).

McConkey agar plates: Moderate growth (30, 37 ° C). Colony morphology is round, smooth and shiny. The color tone is semi-transparent pale yellow, and the periphery is orange.

Tryptic Soy agar plate: 30
Moderate growth at ℃. Colony morphology is round, smooth and shiny. The color tone is light yellowish brown, and the periphery of the village is semi-transparent. Control bacterium Xanthomonas maltophilia ATCC 13637
(Type strain) had a very similar colony appearance to this bacterium. These bacteria grew when 3% of sodium chloride was added to the medium, but the growth was inhibited when 10% of sodium chloride was added (30 ° C).

(C) Storage property Tryptic Soy agar slant medium: 1 at 8 ° C.
It could be stored for months. However, the fungus was killed by the stored slant after 6 months or more.

-80 ° C storage method: Tryptic So
y Storage in liquid medium (8% DMSO added) in the frozen state was possible for at least 1 year.

(D) Physiological properties (i) Aerobic bacteria, no anaerobic growth. (ii) Growth temperature: Growth at 30 and 37 ° C (+), growth at 42 ° C (-). (iii) Oxidase: Positive (+). (iv) Availability of nitrate: negative (-). This bacterium contains KNO ₃
Do not use as a source. (v) Urease: negative (-). (vi) Decarboxylase: lysine decarboxylase (+), arginine dihydrolase (-), ornithine decarboxylase (-). (vii) Protease: Casein hydrolysis (+), gelatin hydrolysis (+). (viii) Lipase activity: positive (+). Hydrolytic activity was observed for Tween 80.

(Ix) Acid production from sugar (30 ° C.): The following results were obtained in a sugar-added ammonium medium. Glucose (-),
Cellobiose (-), maltose (+), fructose (-), arabinose (-), glycerol (-), lactose (-), trehalose (-), xylose (-).

(X) Utilization of sugar (30 ° C.): The following results were obtained in a sugar-added ammonium medium and a minimal medium. Glucose (+), cellobiose (+), maltose (+), lactose (+), trehalose (+).

(Xi) Degradability of starch: negative (-). (xii) ONPG test: positive (+). (xiii) Utilization of citric acid: negative (-) (Simmon's citra
te medium). (xiv) Methionine auxotrophy: L-methionine auxotrophy was recognized in both the agar plate and the liquid medium. Xanthomonas maltophilia (ATCC 1363)
7 (type strain) also had an L-methionine requirement (liquid culture). Formation of (xv) indole: negative (-) (30, 37 ° C).

(E) Production of yellow pigment: The presence of yellow pigment in the cells was confirmed. This dye lacked the two absorption maxima in the wavelength range 425-475 nm reported for xanthmonadine. Therefore, it is considered that the pigment produced by this bacterium is not xanthmonadine. (F) Quinone type: Ubiquinone (+), Menaquinone (-). (G) Analysis of microbial cell fatty acid composition: After freeze-dried microbial cells were subjected to methanolysis and analyzed by GC-MS, branched chain fatty acids were detected. As characteristic fatty acids, iso- and an
It contained teiso-type C15: 0 fatty acids.

The above-mentioned mycological properties are determined by Bergey's
manual of Determinative B
activity vol. 1 p185-18
6 (1984), International Jou
rnal of Systematic Bacter
iology vol. 23 p333-339 (19
73), and Identification Meth
ods in Applied and Enviro
nmental Microbiology vol.
As a result of searching according to the classification criteria of 29 p1-19 (1992), this bacterium was identified as Xanthomonas maltophilia.

[0046]

Example 2 (Xanthomonas maltophilia AJ
12980 (FERM P-14298) Degradation test of isolated soybean protein) Adipron SU (isolated soybean protein, manufactured by Ajinomoto Co., Inc.) 5%
Glucose 7.0%, adipron SU (isolated soybean protein, manufactured by Ajinomoto Co., Inc.) 1.5 in 16 ml (0.8 g) of the suspension.
%, Casein 1.5%, corn steep liquor 1.0
%, Potassium dihydrogen phosphate 0.25%, magnesium sulfate heptahydrate 0.02% in a medium (pH 7.0) 3
4 ml of a culture solution of Xanthomonas maltophilia AJ12980 (FERM P-14298) cultivated at 0 ° C for 48 hours and ethanol (3%) were added, and the mixture was aseptically reacted at 40 ° C for 10 days. Then, the decomposed product was centrifuged to obtain a decomposed filtrate. Table 1 shows the results of quantifying the total nitrogen, the formol nitrogen and the amount of glutamic acid in the decomposition filtrate.

[0047]

[Table 1]

As shown in the table, it is presumed that the raw material protein was almost completely decomposed from the decomposition rate shown as formol nitrogen / total nitrogen and the amount of glutamic acid showing umami as compared with the case where no enzyme was treated. Therefore, the obtained decomposition filtrate can be used as it is as an excellent amino acid seasoning liquid.

[0049]

Example 3 (Xanthomonas maltophilia AJ
12980 (FERM P-14298) defatted soybean decomposition test) 130 g of water was added to 100 g of defatted soybean, and 120 ° C.
After heat sterilization for 40 minutes, cool and add glucose 7.0
%, Adipron SU (isolated soy protein, manufactured by Ajinomoto Co., Inc.)
Medium (pH 7.0) containing 1.5%, casein 1.5%, corn steep liquor 1.0%, potassium dihydrogen phosphate 0.25%, and magnesium sulfate heptahydrate 0.02%.
Xanthomonas maltophilia AJ12980 (FERM P-14298) cultured at 30 ° C for 48 hours
400 ml of culture medium and ethanol (3%) were added,
The reaction was performed aseptically at 40 ° C. for 10 days. Then, the decomposed product was centrifuged to obtain a decomposed filtrate. Table 2 shows the results of quantifying the total nitrogen, formol nitrogen and the amount of glutamic acid in the decomposition filtrate.

[0050]

[Table 2]

As is apparent from the table, it is presumed that the raw material protein was almost completely decomposed from the decomposition rate shown as formol nitrogen / total nitrogen and the amount of glutamic acid exhibiting the umami.

As is clear from these results, the proteolytic filtrate obtained by the present invention is a substance having a higher degree of decomposition and a higher glutamic acid content than the conventionally known enzymatic decomposing solutions such as soy sauce. The decomposition rate is almost equal to that of the liquid. Therefore, the obtained decomposition filtrate can be used as it is as an excellent amino acid seasoning liquid.

[0053]

INDUSTRIAL APPLICABILITY According to the present invention, by using a culture solution of a Xanthomonas genus bacterium which produces proteolytic enzymes excellent in various proteolytic ability, it is possible to obtain various types of bacteria which have low utility value and are hardly decomposed by conventional enzymes. It is possible to obtain a protein hydrolyzate having a high decomposition rate, a high glutamic acid content, and an excellent taste property under neutral and mild conditions. At the same time, it is possible to solve the problems of disposal of processing by-products and the conventional problems associated with the acid decomposition method. Further, a novel strain of Xanthomonas maltophilia AJ12980 (FERM P-14298) obtained by the present invention
Are particularly suitable for the production of protein hydrolysates.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area // A23L 1/228 (C12N 1/20 C12R 1:64) (C12N 9/52 C12R 1:64) (C12P 21/06 C12R 1:64) (72) Inventor Shun Iizuka 1-1, Suzuki-cho, Kawasaki-ku, Kanagawa Prefecture Ajinomoto Co., Inc. Central Research Laboratory (72) Ichiro Takase 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Ajinomoto Co., Inc. Central Research Institute (72) Inventor Shigeru Yamanaka 1-1, Suzuki-cho, Kawasaki-ku, Kanagawa Prefecture Ajinomoto Co., Inc. Central Research Institute (72) Inventor Tadashi Yoshimoto 1-14, Bunkyo-cho, Nagasaki-shi, Nagasaki Nagasaki University Faculty of Pharmaceutical Sciences

Claims (5)

[Claims] 1. Xanthomonas maltophilia AJ1298 producing a protein hydrolase having high activity.
0 (FERM P-14298). 2. An enzyme preparation for protein hydrolysis containing as an active ingredient a protein hydrolase obtained by culturing a microorganism belonging to the genus Xanthomonas. 3. A protein hydrolyzate characterized in that a culture containing a protein hydrolase obtained by culturing a microorganism belonging to the genus Xanthomonas or a fraction thereof is allowed to act on a protein to hydrolyze the protein. Manufacturing method. 4. The microorganism belonging to the genus Xanthomonas is Xanthomonas maltophilia AJ12980 (F
ERM P-14298), The method for producing a protein hydrolyzate according to claim 3, which is characterized in that 5. The method for producing a protein hydrolyzate according to claim 3 or 4, wherein the protein is selected from defatted soybean and isolated soybean protein.