JPH1175885A - Production of calcium 2-hydroxy-4-methylthiobutanoate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for readily producing calcium 2-hydroxy-4- methylthiobutanoate without bi-producing polycalcium-2-hydroxy-4- methylthiobutanoates in high yield by a method not inducing a problem of treating an inorganic salt waste. SOLUTION: This calcium 2-hydroxy-4-methylthiobutanoate composition is produced by hydrolyzing 2-hydroxy-4-methylthiobutyronitrile with a fungus or its treated substance of a microorganism belonging to genus Variororax or genus Arthrobacter to obtain ammonium 2-hydroxy-4-methylthiobutanoate and bringing into contact with a calcium source selected from calcium oxide, calcium hydroxide and calcium carbonate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a solid methionine-like substance which is used as a feed additive.
The present invention relates to a method for producing calcium hydroxy-4-methylthiobutanoate.

[0002]

2. Description of the Related Art Conventionally, various methods have been known for producing calcium 2-hydroxy-4-methylthiobutanoate, but in each case, 2-hydroxy-4-methylthiobutyronitrile is converted to sulfuric acid or phosphoric acid. To produce 2-hydroxy-4-methylthiobutanoic acid calcium salt using 2-hydroxy-4-methylthiobutanoic acid obtained by hydrolysis with a mineral acid. However, in these methods, large amounts of inorganic salts such as calcium sulfate and calcium phosphate are formed as by-products, and the problem of separation treatment of the inorganic salt waste has been pointed out.

Further, a calcium source such as calcium hydroxide, which is a raw material, is used in an amount at least twice the amount required for producing calcium 2-hydroxy-4-methylthiobutanoate,
It is disadvantageous in terms of manufacturing cost. In addition, when hydrolyzing 2-hydroxy-4-methylthiobutyronitrile with a mineral acid, it is necessary to heat, and as a result, polymers of 2-hydroxy-4-methylthiobutanoic acid are by-produced. The effect of the calcium salt of 2-hydroxy-4-methylthiobutanoic acid is reduced.

[0004] These known methods are described in detail below.
U.S. Pat. Nos. 2,745,745 and 2,938
In the method disclosed in the specification of Patent No. 053, 2-hydroxy-4-methylthiobutyronitrile is heated and hydrolyzed with sulfuric acid, and then calcium carbonate is added, and ammonium 2-hydroxy-4-methylthiobutanoate and calcium sulfate are added. Then, calcium sulfate was filtered off, and calcium hydroxide was added to the filtrate to obtain calcium 2-hydroxy-4-methylthiobutanoate. In this case, there is a problem of waste treatment of calcium sulfate, and the raw material calcium source is wasted.

In the method disclosed in US Pat. No. 3,117,000, 2-hydroxy-4-methylthiobutyronitrile is heated and hydrolyzed with sulfuric acid to give an aqueous solution containing 2-hydroxy-4-methylthiobutanoic acid and ammonium bisulfate. And ammonium bisulfate was added thereto to give 2-
Hydroxy-4-methylthiobutanoic acid as an organic layer,
After separating from a saturated aqueous solution of ammonium bisulfate, calcium carbonate was added to obtain calcium 2-hydroxy-4-methylthiobutanoate. Also, UK Patent 91519
In the method disclosed in No. 3, 2-hydroxy-4-
Methylthiobutyronitrile is similarly heated and hydrolyzed with sulfuric acid, and the resulting 2-hydroxy-4-methylthiobutanoic acid is extracted with an organic solvent such as isopropyl ether, separated from an aqueous ammonium bisulfate solution, and calcium carbonate is added thereto. Calcium hydroxy-4-methylthiobutanoate has been obtained. These two methods also have the problem of waste disposal of ammonium bisulfate.

In the method disclosed in British Patent No. 1080667, 2-hydroxy-4-methylthiobutyronitrile is heated and hydrolyzed with phosphoric acid to produce 2-hydroxy-4-methylthiobutanoic acid and ammonium phosphate. Calcium hydroxide was added thereto, and 2-hydroxy-
The calcium phosphate was filtered off as ammonium 4-methylthiobutanoate and calcium phosphate, and calcium hydroxide was added to the filtrate to obtain calcium 2-hydroxy-4-methylthiobutanoate. in this case,
The problem of waste treatment of calcium phosphate arises, and the raw material calcium source is wasted.

[0007] US Pat. No. 4,310,690 discloses a method for producing calcium 2-hydroxy-4-methylthiobutanoate which solves the problem of treating a large amount of inorganic salt waste. In this method, 2-hydroxy-
4-Methylthiobutyronitrile is hydrolyzed by heating with hydrochloric acid to obtain an aqueous solution of 2-hydroxy-4-methylthiobutanoic acid and ammonium chloride. -Converted to an aqueous solution of methylthiobutanoic acid and sodium chloride,
Calcium hydroxide was added thereto, and 2-hydroxy-4-
A calcium methylthiobutanoate is produced, and the concentration, pH and temperature of sodium chloride are delicately controlled to crystallize calcium 2-hydroxy-4-methylthiobutanoate, which is obtained by filtration. The aqueous sodium chloride solution produced as a filtrate at this time is recycled for adjusting the salt concentration for crystallization of calcium 2-hydroxy-4-methylthiobutanoate. However, this method requires extremely delicate control of sodium chloride concentration, pH and temperature during the production process, and causes loss of calcium 2-hydroxy-4-methylthiobutanoate to the filtrate, There is a drawback that the filtrate must be recovered and used, and the operation is extremely complicated. It is also disadvantageous in that sodium hydroxide is required as an extra raw material.

[0008] Heat hydrolysis of 2-hydroxy-4-methylthiobutyronitrile with a mineral acid produces polymers of 2-hydroxy-4-methylthiobutanoic acid as by-products, resulting in diminished feed effect. U.S. Pat. No. 3,272,860 discloses a process for preparing a calcium salt of 2-hydroxy-4-methylthiobutanoic acid having a high monomer content except for a monoalkyl ether of glycol, except for calcium salts of poly-2-hydroxy-4-methylthiobutanoic acid. Have been.

On the other hand, as a microorganism capable of producing 2-hydroxy-4-methylthiobutanoic acid by hydrolyzing 2-hydroxy-4-methylthiobutyronitrile,
No. 40898 discloses microorganisms belonging to the genera Caseobacter, Pseudomonas, Alcaligenes, Corynebacterium, Brevibacterium, Nocardia, Rhodococcus and Arthrobacter, and WO 9
6/09403 lists microorganisms belonging to the genus Alcaligenes, Rhodococcus and Gordona.
No. 175, Pantoea, Micrococcus,
Bacteria, Bacillus, Actinomadura, Kitassatosbora, Vilimeria, Achromobacter,
Beijerinkia, Cellulomonas, Klebsiella, Actinoborisbora, Actinosinnema, Actinoplanes, Amycolata, Saccharopolyppola, Streptomyces, Nocardioides, Providencia, Microbacterium, Rhodobacter And microorganisms of the genus Rhodospirillium.

[0010]

However, 2-hydroxy-4 obtained by hydrolysis with the above-mentioned mineral acids such as sulfuric acid and phosphoric acid.
Specific conditions are also required in the reaction for producing a calcium salt of 2-hydroxy-4-methylthiobutanoic acid by contacting a calcium source with -methylthiobutanoic acid, and 2-hydroxy-4-methylthiobutane obtained using a microorganism is required. It has not been known that when a calcium source is brought into contact with a reaction product containing an acid without special treatment, a calcium salt of 2-hydroxy-4-methylthiobutanoic acid can be efficiently obtained.

[0011] Then, 2 obtained by using such a microorganism.
The fact that it was not known to produce a calcium salt of 2-hydroxy-4-methylthiobutanoic acid by contacting a calcium source with a reactant containing -hydroxy-4-methylthiobutanoic acid, is due to the fact that many of the above-mentioned known microorganisms are used. In some cases, the accumulation concentration of the product, 2-hydroxy-4-methylthiobutanoic acid, is low, and the calcium source is brought into contact with such a low concentration of 2-hydroxy-4-methylthiobutanoic acid-containing liquid. This is because it was considered that production of calcium 2-hydroxy-4-methylthiobutanoate at a practical level could not be achieved at all.

An object of the present invention is to provide an inorganic salt waste by using a microorganism capable of producing 2-hydroxy-4-methylthiobutanoic acid with high efficiency by hydrolyzing 2-hydroxy-4-methylthiobutyronitrile. A high-yield, simple 2-form that does not cause any processing problem and does not produce calcium poly-2-hydroxy-4-methylthiobutanoate.
An object of the present invention is to provide a practical method for producing calcium hydroxy-4-methylthiobutanoate.

[0013]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors hydrolyze 2-hydroxy-4-methylthiobutyronitrile to efficiently produce 2-hydroxy-4-methyl-4-butyronitrile.
A microorganism capable of producing methylthiobutanoic acid was searched for, and a desired activity was found for a microorganism belonging to the genus Variovorax and a microorganism belonging to the genus Arthrobacter, and 2-hydroxy-4- Methylthiobutyronitrile is hydrolyzed at room temperature to obtain 2-hydroxy-
A calcium source such as calcium oxide, calcium hydroxide or calcium carbonate is added to an aqueous solution of ammonium 4-methylthiobutanoate, and water is distilled off and dried to obtain a powdery calcium salt of 2-hydroxy-4-methylthiobutanoate. It has been confirmed that the composition can be obtained efficiently, and the present invention has been completed.

That is, the present invention relates to 2-hydroxy-4-
Ammonium 2-hydroxy-4-methylthiobutanoate obtained by biologically hydrolyzing methylthiobutyronitrile may be used in combination with one or more selected from calcium oxide, calcium hydroxide, calcium carbonate and the like. A method for producing calcium salt of 2-hydroxy-4-methylthiobutanoic acid, characterized by contacting with a calcium source of
The present invention relates to a feed containing calcium methylthiobutanoate.

The present invention also relates to 2-hydroxy-4-methylthiobutyronitrile, which is used in the preparation of Variovorax (Vario Vox).
vorax) cells of microorganisms belonging to the genus or processed products thereof,
Or Arthrobacter
r) Hydrolysis using microorganisms belonging to the genus Arthrobacter, such as NSSC104 strain, or a processed product thereof, and adding 2-hydroxy-4-methylthiobutanoic acid ammonium salt to calcium oxide, calcium hydroxide and carbonate Contacting one or more calcium sources selected from the group consisting of calcium,
The present invention relates to a method for producing calcium 4-methylthiobutanoate, and a feed containing the calcium 2-hydroxy-4-methylthiobutanoate produced by such a method.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, "biological hydrolysis" refers to hydrolysis utilizing enzymatic activity derived from organisms such as microorganisms. Examples of the microorganism used include a microorganism having a nitrile hydrolase activity capable of efficiently hydrolyzing 2-hydroxy-4-methylthiobutyronitrile to ammonium 2-hydroxy-4-methylthiobutanoate. Although any organism such as a recombinant microorganism can be used, preferably, 2-hydroxy-
4-methylthiobutyronitrile or 2-hydroxy-4
-It is preferable to have a resistance to the concentration of ammonium methylthiobutanoate and a durability having a long-lasting activity.

That is, after the hydrolysis reaction, a high-concentration aqueous solution (15% by weight or more) of ammonium 2-hydroxy-4-methylthiobutanoate is given to maintain the activity to withstand continuous use for many hours or repeated use many times. It is preferable to use a microorganism having a property. By using such a microorganism, the energy cost in the step of distilling and drying water after adding the calcium source can be reduced, and the productivity can be increased and the catalyst cost can be reduced.

A specific example of such a microorganism is Varioborax pardoxus.
(adoxus) IAM12374 and Arthrobacter NSSC104 (FER
MBP-5829). Among these microorganisms, Variovorax paradoxus IAM1
2374 can be easily obtained from the Institute for Molecular and Cellular Biology (IAM) of the University of Tokyo. Also Arthrobacter N
The SSC 104 has been newly separated from nature by the present inventors and deposited as follows. Accession number: FERM BP-5829
Date of deposit: Deposited in Japan on February 6, 1996, February 1997
Transfer of international deposit on March 20 Deposit place: 1-3-1, Higashi, Tsukuba, Ibaraki, Japan Depositary organization: Biotechnology Industrial Technology Research Institute, Ministry of International Trade and Industry

The mycological properties of Arthrobacter NSSC104 are as follows. Form Polymorphic Bacillus Gram stain + rod-coccus cycle + spore-motility-cell wall diamino acid lysine Attitude to oxygen aerobic oxidase-catalase + DNA degradation + gelatin liquefaction + starch degradation + casein degradation + Vitamin requirement-Glycolyl test-(acetyl type) quinone MK-9 (H2) Cell wall sugar composition Galactose + Glucose +

The mycological properties described above were determined by Bergey's
Manual of Systematic Bact
As a result of a search based on eriology (1986), NSSC104 strain was found to be Arthrobacter (Arthrr).
obacter). This strain has been deposited with the National Institute of Advanced Industrial Science and Technology under the above deposit number.

The cultivation of the microorganism used in the present invention is carried out in a usual medium containing an enzyme inducer, a carbon source, a nitrogen source, an inorganic ion and, if necessary, an organic nutrient which the microorganism can utilize. Examples of the enzyme inducer include nitrile compounds such as isobutyronitrile, and cyclic amide compounds such as ε-caprolactam. As the carbon source, carbohydrates such as glucose, alcohols such as ethanol, organic acids and the like are appropriately used. Amino acids,
Nitrate, ammonium salt and the like are used. As the inorganic ion, a phosphate ion, a potassium ion, a magnesium ion, a sulfate ion, an iron ion and others are used as needed. As organic nutrients, vitamins, amino acids, etc. and corn steep liquor containing them,
Yeast extract, polypeptone, meat extract, and others are appropriately used. The culture is carried out under aerobic conditions, pH 6-9, temperature 2
What is necessary is just to control it in the suitable range of 5-37 degreeC, and to carry out.

In the hydrolysis reaction of the microorganism used in the present invention, the cells cultured as described above are collected and used as they are, or immobilized cells are used as necessary, or the cells are treated. Thus, the treatment is carried out by preparing a treated product of cells such as a crude enzyme and an immobilized enzyme, and bringing them into contact with 2-hydroxy-4-methylthiobutyronitrile in an aqueous solvent.

When immobilizing cells or enzymes, commonly used immobilization techniques such as a carrier binding method and an inclusive method can be applied. In the case of preparing a crude enzyme, a commonly used enzyme purification technique such as salting out ammonium sulfate, chromatography and the like can be applied after crushing the cells with ultrasonic waves, a high-pressure homogenizer or the like. The cells are used at a concentration of 0.01 to 10% by weight in terms of dry weight, and after completion of the reaction, they are collected by filtration or centrifugation and can be repeatedly used for the hydrolysis reaction. Examples of the aqueous solvent include an aqueous solution containing water, a salt such as a buffer, or an organic solvent, and these may be separated into two phases.

The hydrolysis is carried out by suspending the cells or the treated cells prepared as described above in an aqueous solvent, and adding 2-hydroxy-4-methylthiobutyronitrile thereto sequentially or continuously. It can be carried out. The pH of the reaction solution is adjusted to 5 with an appropriate buffer or acid or alkali.
The reaction temperature may be maintained at a normal temperature of 15 to 35 ° C. Thus, the 2-hydroxy-4-methylthiobutyronitrile ammonium salt corresponding to the added 2-hydroxy-4-methylthiobutyronitrile is accumulated at a high concentration of 15% by weight or more in 6 to 120 hours.

Next, the cells or the treated product are removed by filtration or centrifugation to obtain an aqueous solution of ammonium 2-hydroxy-4-methylthiobutanoate. The separated or removed cells or the treated product can be repeatedly used for the hydrolysis reaction without a substantial decrease in activity. Further, the reaction solution is continuously treated by a centrifuge or a membrane filter to separate the cells or the treated product thereof from an aqueous solution of ammonium 2-hydroxy-4-methylthiobutanoate. The continuous reaction used is also possible.

Subsequently, the obtained aqueous solution of ammonium 2-hydroxy-4-methylthiobutanoate is used as it is and mixed with a calcium source. As a calcium source, 2-hydroxy-4-methylthiobutanoic acid calcium salt can be obtained efficiently and without producing undesirable by-products when brought into contact with ammonium 2-hydroxy-4-methylthiobutanoate. Any material may be used as long as it is used, and in some cases, two or more calcium sources may be used in combination. Among the calcium sources, calcium oxide, calcium hydroxide or calcium carbonate is particularly preferred.

[0027] The calcium source may be used as a powder or as a suspension in water. The addition amount of the calcium source is 2-
Ammonium hydroxy-4-methylthiobutanoate 1
It is arbitrarily selected from the range of 0.3 to 0.6 mol per mol. Immediately after mixing, water is distilled off under reduced pressure or normal pressure at 40 to 100 ° C. At this time, the ammonia also evaporates and can be recovered as needed. Thus, calcium 2-hydroxy-4-methylthiobutanoate is obtained as a free-flowing powder.

The calcium 2-hydroxy-4-methylthiobutanoate of the present invention thus obtained is usually obtained as a mixed composition with a small amount of ammonium 2-hydroxy-4-methylthiobutanoate, When used as an agent, it is advantageous to use such a composition as it is, but if necessary, the ammonium salt of 2-hydroxy-4-methylthiobutanoic acid can be removed from the composition.

[0029]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. In the examples, analysis of organic substances was performed by high performance liquid chromatography, and analysis of ammonia was performed by N
UV Absorbance Measurement Using ADH-Glutamate Dehydrogenase (Methods of Enzymatic)
Analysis, Bergmeyer H .; U.
ed. , Vol. 8, pp. 454-461).

Example 1 2 ml of a medium containing 0.3% broth, 0.5% peptone and 0.5% salt was placed in a test tube, and 20 ml of a medium having the following composition was placed in a 100 ml baffled Erlenmeyer flask. Sterilized at 121 ° C. for 15 minutes. A loopful of Variovorax paradoxus IAM12374 was inoculated into a 2 ml test tube and cultured with shaking at 30 ° C. overnight.
and transfer it to a baffled Erlenmeyer flask and add 3 more ml.
Shaking culture was carried out at 30 ° C for days. The cells obtained by centrifuging the culture solution are washed with physiological saline, and 1.0% by weight of the cells in terms of dry weight are added to 0.1 M phosphate buffer (pH
7.5).

(Medium composition) Yeast extract 0.5% Glycerol 0.5% Monopotassium phosphate 0.1% Dipotassium phosphate 0.1% Salt 0.02% Magnesium sulfate heptahydrate 0.02% ε- Caprolactam 0.5% pH 7.2 (adjusted with 2N caustic soda)

Then, 2-hydroxy-4-methylthiobutyronitrile was added to the above-mentioned buffer containing the cells at a final concentration of 160 m.
M and a hydrolysis reaction was carried out at 30 ° C. with gentle shaking. The same amount of 2-
Hydroxy-4-methylthiobutyronitrile was repeatedly added 9 times, and the reaction was performed for a total of 120 hours. After completion of the reaction, the reaction solution was centrifuged to remove cells, and a 25% by weight aqueous solution of ammonium 2-hydroxy-4-methylthiobutanoate was obtained as a centrifuged supernatant. (Yield 98%).

Subsequently, 25% by weight of the ammonium salt of 2-hydroxy-4-methylthiobutanoic acid obtained in the above method was placed in a round bottom flask containing 4.3 g of calcium oxide powder.
100 ml of an aqueous solution was added. After the addition, while stirring,
Heated to 100 ° C. to drive off ammonia and water at normal pressure. When about 50 ml of water was distilled off, the temperature of the reaction solution was lowered to 5%.
The temperature was lowered to 0 ° C., and a water pump was connected to further remove ammonia and water under reduced pressure. Distillation subsided in about 30 minutes, and a white powder having free-flowing properties was obtained. However, when water was analyzed, 27% by weight was still remaining, so it was changed to a vacuum pump and dried at 50 ° C. for 1 hour. 25.9 g of a free-flowing white powder were obtained. The analytical values of this white powder are shown below. The recovery of 2-hydroxy-4-methylthiobutanoic acid from the ammonium salt of 2-hydroxy-4-methylthiobutanoic acid obtained by the cell hydrolysis reaction was 99.2% from the following analysis value. (Analytical value) Calcium 2-hydroxy-4-methylthiobutanoate 92.7% by weight Ammonium 2-hydroxy-4-methylthiobutanoate 4.1% by weight Water 3.2% by weight

Example 2 Arthrobacter NS prepared in the same manner as in Example 1
The SC104 strain cells were suspended in distilled water to a dry weight of 3.2% by weight. Next, 2-hydroxy-
4-methylthiobutyronitrile was continuously added at an addition rate of 0.46 g / hr / g of dry cell weight,
The hydrolysis reaction was performed at 30 ° C. for 20 hours while adjusting the pH to 7.4 to 7.6 with 0.5 M aqueous ammonia. After completion of the reaction, the reaction solution was centrifuged to collect the cells. The collected cells were washed three times with 40 times the weight of distilled water, then resuspended in the same amount of distilled water as the first time, and used for the second reaction. 2
The second reaction, cell recovery and cell washing were performed in the same manner as in the first reaction. Such a reaction was repeated 10 times, and the concentration of 2-hydroxy-4-methylthiobutanoic acid contained in the centrifuged supernatant was quantified at each time. The results are shown below.

[0035]

[Table 1]

Subsequently, 100 ml of a 36.4% by weight aqueous solution of the ammonium salt of 2-hydroxy-4-methylthiobutanoic acid obtained in the seventh repetition reaction was placed in a round bottom flask containing 22.2 g of calcium carbonate powder. Was added. After the addition, the mixture was heated to 100 ° C. with stirring to remove carbon dioxide, ammonia and water at normal pressure. When about 50 ml of water was distilled off, the temperature of the reaction solution was lowered to 50 ° C., and a water pump was connected to further remove ammonia and water under reduced pressure. When the distillation was completed, the product was dried at 50 ° C. for 1 hour using a vacuum pump to obtain 39.4 g of a free-flowing white powder. The analytical values of this white powder are shown below. The recovery of 2-hydroxy-4-methylthiobutanoic acid from ammonium 2-hydroxy-4-methylthiobutanoate obtained by the cell hydrolysis reaction was 99.3% based on the following analysis value. (Analytical value) Calcium 2-hydroxy-4-methylthiobutanoate 90.2% by weight Ammonium 2-hydroxy-4-methylthiobutanoate 2.7% by weight Water 7.1% by weight

Example 3 An eggplant-shaped flask containing 8.4 g of calcium hydroxide powder was set on a rotary evaporator, and while rotating,
100 ml of a 36.4% by weight aqueous solution of 2-hydroxy-4-methylthiobutanoic acid ammonium salt obtained by the fifth repetition of the cell hydrolysis reaction in Example 2 was introduced by a tubing pump. Immediately after the introduction, the water pump was operated to reduce the pressure, the temperature of the reaction solution was raised to 50 ° C., and ammonia and water were expelled. When the distillation stopped, the vacuum pump was replaced with a vacuum pump and dried at 50 ° C. for 1 hour to obtain 37.7 g of a free-flowing white powder. The analytical values of this white powder are shown below. In addition, 2-hydroxy-4 from ammonium 2-hydroxy-4-methylthiobutanoate obtained by the cell hydrolysis reaction was used.
-The recovery of methylthiobutanoic acid was 9
It was 9.4%. During the reaction, the ammonia distilled out was dissolved and recovered by passing cooled water through a distilling system between the rotary evaporator and the water jet pump. The recovery rate with respect to the theoretical distillation amount of ammonia was 99.1.
%Met. (Analytical value) Calcium 2-hydroxy-4-methylthiobutanoate 94.7% by weight Ammonium 2-hydroxy-4-methylthiobutanoate 2.4% by weight Water 2.9% by weight

[0038]

According to the present invention, 2-hydroxy-4
-Hydrolysis of methylthiobutyronitrile to produce highly efficient 2
Since 2-hydroxy-4-methylthiobutanoic acid is used as a microorganism, 2-hydroxy-4 which is a kind of solid methionine-like substance used as a feed additive is used.
Not only is it possible to obtain calcium methylthiobutanoate in a high yield and simply, but also the following effects are exhibited, which is suitable and advantageous from the viewpoint of industrialization and practical use. B) 2-hydroxy-4 obtained by biological hydrolysis
-Since calcium 2-hydroxy-4-methylthiobutanoate is produced using ammonium methylthiobutanoate, the amount of the raw material calcium source used can be minimized and no inorganic salt waste is generated. . B) Since 2-hydroxy-4-methylthiobutyronitrile can be hydrolyzed at room temperature, poly-2-hydroxy-4-methylthiobutanoic acid is not formed as a by-product and 2-hydroxy-4-methylthiobutyronitrile obtained by the method of the present invention is not produced. The feed effect of calcium 4-methylthiobutanoate is high. C) Ammonia derived from the nitrogen atom of 2-hydroxy-4-methylthiobutyronitrile can be recovered in a gaseous state or as a concentrated aqueous solution, and is highly useful.

Continuing on the front page (72) Inventor Takahiro Ishikawa 345 Takada, Odawara-shi, Kanagawa Japan Nippon Soda Co., Ltd.Odawara Research Laboratories (72) Inventor Masaji Hatayama 345 Takada, Odawara-shi, Kanagawa Japan Nippon Soda Co., Ltd.

Claims (7)

[Claims] 1. A calcium source is brought into contact with ammonium 2-hydroxy-4-methylthiobutanoate obtained by biologically hydrolyzing 2-hydroxy-4-methylthiobutyronitrile. Hydroxy-
A method for producing calcium 4-methylthiobutanoate. 2. Ammonium 2-hydroxy-4-methylthiobutanoate obtained by hydrolyzing 2-hydroxy-4-methylthiobutyronitrile using microorganisms belonging to the genus Variovorax or a treated product thereof. A method for producing calcium 2-hydroxy-4-methylthiobutanoate, comprising contacting a calcium source with the salt. 3. The method according to claim 1, wherein 2-hydroxy-4-methylthiobutyronitrile is treated with Arthrobacter.
r) contacting a calcium source with ammonium 2-hydroxy-4-methylthiobutanoate obtained by hydrolysis using cells of a microorganism belonging to the genus or a processed product thereof; A method for producing calcium methylthiobutanoate. 4. Arthrobacter
ter) is a microorganism belonging to the genus Arthrobacter (Ar).
4. The process for producing calcium 2-hydroxy-4-methylthiobutanoate according to claim 3, wherein the strain is NSSC104 strain. 5. The method according to claim 2, wherein the cells of the microorganism or the processed product thereof are used repeatedly.
A method for producing calcium hydroxy-4-methylthiobutanoate. 6. The 2-hydroxy-4-one according to claim 1, wherein the calcium source is calcium oxide, calcium hydroxide or calcium carbonate.
A method for producing calcium methylthiobutanoate. 7. A feed containing calcium 2-hydroxy-4-methylthiobutanoate produced by the production method according to any one of claims 1 to 6.