JPH0355114B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a method for producing L-glutamic acid by fermentation. The present inventors have discovered that rice saccharification liquid and cane molasses are
By using rice saccharifier and cane molasses together as carbon sources at a ratio between 25:75 and 75:25, higher yields can be achieved than when using rice saccharifier or cane molasses alone. I learned that L-glutamic acid is produced in This invention was completed as a result of further research based on this knowledge. That is, in the present invention, L-glutamic acid is produced by using rice saccharified liquor and cane molasses together as a carbon source so that the ratio of the rice saccharified liquor and cane molasses is in the range of 25:75 to 75:25. This is a method for producing L-glutamic acid by a fermentation method characterized by culturing production bacteria. The rice saccharification solution can be obtained by pulverizing polished or broken rice, preferably to a finer grain of less than 50 mesh, more preferably finer than 100 mesh, suspending it in water, and subjecting it to enzymatic saccharification by a conventional method. The saccharified liquid after saccharification may be used after being filtered, but it may also be used without filtration. There are many examples of L-glutamic acid viable bacteria used in the present invention, which are so-called coryneform bacteria. Some examples are shown below. Brevibacterium deivalicatum
ATCC14020 Brevibacterium flavum ATCC14067 Brevibacterium lactofamentum
ATCC13869 Corynebacterium acetoacid film
ATCC13870 Corynebacterium glutamicum ATCC13032 Microbacterium ammonia film
ATCC15354 Rice saccharification liquid and cane molasses are prepared in advance at 25:75 or
It may be mixed at a ratio of 75:25 and then mixed with other medium components, or it may be mixed separately with other medium components. The medium used in the present invention may be a normal medium containing medium components commonly used in L-glutamic acid fermentation, except for containing the above-mentioned specific carbon source. There is no need to adopt a method that is particularly different from conventional methods for culturing L-glutamic acid producing bacteria. During cultivation, rice saccharification liquid and cane molasses were mixed with 25:
It may be supplemented to the medium at a ratio of 75 to 75:25. Example 1 Cane molasses (CM) and rice saccharification liquid were mixed in the proportions shown in Table 1 to prepare five types of sugar liquid (A to E).

[Table] A solution (S1) having the composition shown in Table 2 was separately prepared.

[Table] Five 300 ml media were prepared by mixing 50 ml of sugar solution and 250 ml of solution (S1). Initial culture medium (total volume 300ml) for experimental plots 1 to 5 was added to 1
The mixture was poured into a fermenter and sterilized by heating at 115°C for 10 minutes. This was inoculated with Brevibacterium lactofermentum ATCC13869, which had been cultured in advance.
Culture was carried out at 31.5°C with aeration and stirring while maintaining the pH at 7.8 with ammonia gas. During culture, from the point when the glucose concentration in the medium fell below 3%, sugar solution was added to the culture medium little by little, such as sugar solution A was added to experimental section 1 and sugar solution B was added to experimental section 2, and the glucose concentration was increased from 2 to 3%. It was maintained at 4% and cultured for 34 hours. The amount of sugar solution added was unified to 80 ml in each experimental group. In addition, when the predetermined amount of bacteria is reached during the culture, the surfactant Tween 60 is added to the medium.
It was added to make it 0.6%. The fermentation results obtained are shown in Table 3. Experimental areas 2 to 4 where CM and rice saccharification liquid were used together.
The calculated yield is also shown assuming that the sugar yield is the weighted average of the sugar yield in the case of CM or rice saccharified liquid alone in Experimental Groups 1 and 5. The difference between the experimental value and the calculated value is the synergistic effect of the mixed use of CM and rice liquefied liquid.

[Table] Example 2 Five types of sugar solutions (F to J) were prepared by mixing CM and rice saccharification solution in the proportions shown in Table 4.

[Table] A solution (S2) having the composition shown in Table 5 was separately prepared.

【table】

[Table] 100 ml of sugar solutions (F to J) and 200 ml of solution (S2) were mixed to prepare five 300 ml media. The culture media for experimental groups 1 to 5 (total volume: 300 ml) were poured into a 1-volume fermenter and sterilized by heating at 120° C. for 10 minutes. Corynebacterium glutamicum ATCC13032 cultured in advance was inoculated into the sterilized medium and PH
While maintaining the temperature of 7.8 with ammonia gas, the culture was carried out under aeration and stirring. During the culture, when a predetermined amount of bacteria was reached, the surfactant Tween 60 was added at a concentration of 0.3% based on the volume of the medium. Table 6 shows the amount of glutamic acid produced and the sugar yield obtained during 30 hours of culture, and also shows the results for experimental groups 2 to 4.
As in Example 1, the yield was compared with the calculated yield.

[Table] Example 3 CM and rice saccharified liquid were mixed in the proportions shown in Table 7 to prepare five types of sugar liquid (K to O).

[Table] A solution (S3) having the composition shown in Table 8 was separately prepared.

[Table] 100 ml of sugar solution (K to O) and 200 ml of solution (S3) were mixed to prepare five 300 ml media. The culture media for experimental groups 1 to 5 (total volume: 300 ml) were poured into a 1-volume fermenter and sterilized by heating at 120° C. for 10 minutes. The sterilized medium was inoculated with Brevibacterium flavum ATCC 14067, which had been cultured in advance, and cultured under aeration and agitation while maintaining the pH at 7.8 with ammonia gas. During the culture, when a predetermined amount of bacteria was reached, the surfactant Tween 60 was added to the culture medium at a concentration of 0.4%. Table 9 shows the amount of glutamic acid produced and the sugar yield obtained during 32 hours of culture, and also shows the results for experimental groups 2 to 4.
As in Examples 1 and 2, the yield was compared with the calculated yield.

【table】 [Brief explanation of drawings]

Figures 1-3 are diagrams showing the relationship between the sugar yield and the calculated yield with respect to the blending ratio of Kenmolasses (CM) and rice saccharification liquid. The vertical axis shows the sugar yield (%) and the calculated yield (%), and the horizontal axis shows the blending ratio of Kenmoraces (CM) and rice saccharification liquid. ×---×: Calculated value, ●---●: Indicates the sugar yield of the present invention.

Claims (1)

[Claims] 1. Rice saccharification liquid and cane molasses start from 25:75.
So that the ratio is in the range up to 75:25,
A method for producing L-glutamic acid by a fermentation method, which comprises culturing L-glutamic acid-producing bacteria using a combination of rice saccharification liquid and cane molasses as carbon sources.