JPH0528112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention improves a method for producing L-glutamic acid by a fermentation method.

[Conventional technology]

Regarding the ability of microorganisms belonging to the genus Bacillus to produce L-glutamic acid, for example, the Journal of the Japanese Society of Agricultural Chemistry, Vol. 33, p. 843 (1959) describes
It has been reported that Bacillus megaterium produces approximately 3 g/dl of L-glutamic acid from glucose, and in the same magazine, Vol. 34, page 70 (1960), it was reported that Bacillus megaterium produces 0.5 g/dl of L-glutamic acid from glucose. There is. Also, in the same magazine, Vol. 34, p. 592 (1960), it is reported that Bacillus auxotrophic bacteria produce 1 g/dl or more of L-glutamic acid from glucose. The culture temperature of Bacillus bacteria in these reports is all 30°C.

On the other hand, regarding microorganisms of the genus Arthrobacter, for example, it was announced at the Japanese Society of Agricultural Chemistry Conference in 1962 that Arthrobacter citreus produces L-glutamic acid from glucose at a yield of 30% in the presence of penicillin. (Page 173 of the collection of lecture abstracts). This culture temperature is also around 30°C.

It is not known that these microorganisms can be cultured at high temperatures above 45°C to produce L-glutamic acid, and it is also known that L-glutamic acid production by Bacillus bacteria is caused by the addition of surfactants such as Tween or penicillin. It is also unknown that the production of L-glutamic acid by Arthrobacter bacteria is promoted by the addition of a surfactant.

[Problem that the invention seeks to solve]

Since L-glutamic acid is an amino acid that is produced in large quantities, it is important to improve its productivity.

Additionally, in order to maintain the fermentation temperature at the optimum temperature of around 30°C, it is necessary to remove the fermentation heat generated during culture, but in the case of large-scale fermenters, the cost of cooling energy required for this removal is significant. It had become a thing.

[Means for solving problems]

The present invention provides a method for producing L-glutamic acid that solves these problems, and by culturing specific microorganisms at high temperatures, the production rate of L-glutamic acid is increased and cooling costs are reduced. This was done after discovering that something could be done.

That is, the present invention provides 45 microorganisms belonging to the genus Bacillus or Arthrobacter that can grow at 45°C or higher and can produce L-glutamic acid in a liquid medium.
The present invention relates to a method for producing L-glutamic acid, which is characterized by culturing aerobically at a temperature of .degree. C. to 60.degree. C. to produce and accumulate L-glutamic acid, and collecting the L-glutamic acid.

Microorganisms that can be used in the method of the present invention belong to the genus Bacillus or Arthrobacter and must be capable of producing L-glutamic acid, and must be able to grow at 45°C or higher. Since this growth is accompanied by the production of L-glutamic acid, the growth must be good, and those that can grow well even at 50° C. or higher are particularly preferred. Examples of such microorganisms include Bacillus brevis FERM P-3194 and B.megaterium AJ.
1273, AJ 1361, B.pumilum
AJ 1280, B.subtilis AJ 1250,
Same AJ 1260, Same AJ 1299, Same AJ 1713, Same AJ
3265, B.licheniformis AJ
1352, AJ 3288, Coagulance (B.
coagulans) AJ 1370, B.sp. AJ
It also exists in 3298 etc. Regarding the Arthrobacter genus, Arthrobacter tumescens ATCC 15799 and Arthrobacter simplecus (A.
simplex) also exists in AJ 3223 etc.

The nutritional components added to the medium may be the same as those for general media for culturing Bacillus bacteria or Arthrobacter bacteria, such as starch, glucose, sucrose, carbon sources such as these substances, ammonium sulfate, ammonium chloride, Ammonium salts such as ammonium nitrate, nitrogen sources such as ammonia, urea, amino acids, phosphates,
Inorganic salts such as magnesium salts, iron salts, and manganese salts, vitamins, and organic nutrients such as meat extracts, peptone, and soybean protein hydrolyzate are added in appropriate combinations.

Adding a surfactant to the medium is important in promoting the production of L-glutamic acid. The surfactant may be the same as the usual surfactant known for general L-glutamic acid producing bacteria belonging to the genus Brevibacterium or Corynebacterium, such as polyoxyethylene sorbitan monolaurate, polyoxyethylene, etc. Sorbitan monooleate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, etc. can be used. The amount added is
Approximately 0.05 to 5%, particularly 0.1 to 1% is appropriate.

It is also preferable to add penicillin to the medium to promote the production of L-glutamic acid.
The appropriate amount to add is about 0.1 U/ml to 10 U/ml.

The culture temperature should be 45°C to 60°C, especially 50°C to 60°C.
It is preferable to set it as °C. Other culture conditions may be the same as normal conditions, and optimal conditions may be set depending on the microorganism used. Incubation time is generally 20
About ~50 hours is sufficient, and in particular, about 20 to 30 hours is often sufficient. During cultivation, aeration and stirring are performed as appropriate.

[Effect]

By fermenting at high temperatures, the fermentation rate can be increased 2 to 3 times the conventional rate. Moreover, a cooling medium at room temperature can be used, and the cooling medium discharged from the fermentation layer is heated by the heat of fermentation.

〔Example〕

Example 1 Starch 5% Salt Ammonium 2% MgSO ₄・7H ₂ O 0.1% K ₂ HPO ₄ 0.2% Mn ⁺⁺ 2ppm Fe ⁺⁺ 2ppm Soybean protein hydrolyzate (“taste liquid”) 0.5% Meat extract 1% CaCO _3.5 % 50 ml of each medium having the above composition was placed in a 500 ml Sakaguchi Kolben and sterilized by heating at 120°C for 10 minutes.

Add 2.5 ml of the seed culture of each strain shown in the table below obtained by culturing at 50°C for 10 hours in a bouillon medium containing 1% meat extract, 1% peptone, and 0.5% NaCl to the above heat-sterilized medium. After inoculation, polyoxyethylene sorbitan monostearate was added to each medium to a concentration of 0.2%. each
After culturing with shaking at 50°C for 20 hours, the L-glutamic acid concentration of the culture solution was measured, and the results shown in the table below were obtained.

L -glutamic acid bacteria strain production amount Vacillus / Mega Terium 1.2 g / DL AJ 1273 Bacillus Brevis 1.1 Ferm P -3194 Bacillus Zubuchiris 1.0 AJ 1250 Bacillus Rhehenjol Miss 1.3 AJ 1352 Bacillus Koagiywrans 1.1 AJ 1370 Example 2 Same as Example 1 50 ml of each medium with the same composition was added to a 500 ml Sakaguchi Kolben and sterilized by heating at 120°C for 10 minutes.

Add 2.5 ml of the seed culture of each strain shown in the table below obtained by culturing in bouillon medium at 50°C for 15 hours to the above heat-sterilized medium for inoculation, and further add polyoxyethylene sorbitan monopalmitate to each medium. was added to a concentration of 0.2%. each at 50℃
After culturing with shaking for 20 hours, the L-glutamic acid concentration of the culture solution was measured, and the results shown in the table below were obtained.

L-glutamic acid bacteria Strain Production amount Arthrobacter 0.9 g/dl Tributescens ATCC 15799 Arthrobacter 1.1 g/dl Simplex AJ 3223 [Effects of the invention] By the method of the present invention, the L-glutamic acid fermentation rate is stopped and fermentation is carried out. Cycles can be shortened and fermentation equipment can be used more efficiently. Since room-temperature water can be used as the cooling medium sent to the fermenter, a cooler for cooling this refrigerant is not required. Furthermore, the amount of this refrigerant itself is smaller than before. Furthermore, since the refrigerant discharged from the fermenter is heated, this heat can be effectively used for other purposes. As a result, the fermentation apparatus can be downsized, some parts can be omitted, energy can be saved and used effectively, and the manufacturing cost of L-glutamic acid can be reduced.

Claims (1)

[Claims] 1 Belongs to the genus Bacillus or the genus Arthrobacter45
It is characterized by culturing microorganisms that can grow above ℃ and produce L-glutamic acid aerobically in a liquid medium at 45℃ to 60℃, producing and accumulating L-glutamic acid therein, and collecting it. A method for producing L-glutamic acid. 2. The manufacturing method according to claim 1, wherein the microorganism is cultured in a liquid medium containing 0.05% to 5% of a surfactant. 3 Add penicillin to the microorganisms at 0.1 U/ml to 10 U/ml.
The manufacturing method according to claim 1, which comprises culturing in a liquid medium containing ml.