JPH0420599B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing L-glutamic acid by a fermentation method, and more particularly, the present invention relates to a method for producing L-glutamic acid by a fermentation method, and more particularly, the present invention relates to a method for producing L-glutamic acid by a fermentation method, which is characterized in that the fermentation yield is improved by using beet juice or a cation exchange resin adsorption solution of beet molasses. This invention relates to a method for producing glutamic acid. Cane molasses, beet molasses, and glucose (starch saccharified liquid) are mainly used as raw materials for L-glutamic acid fermentation. Among these, the L-glutamic acid fermentation method using beet molasses as a carbon source is known to be superior in terms of fermentation yield compared to cases using cane molasses or glucose. In addition, a method has already been developed in which a substance that improves the fermentation yield in beets or beet molasses is extracted with an organic solvent and the extract is used to ferment and improve the yield (see Japanese Patent Publication No. 12111/1983). ). However, this method is not economically viable because it requires the use of a large amount of organic solvent to extract the active ingredient, and it also requires recovery and purification of the organic solvent used for extraction. However, it has not yet been implemented industrially. In view of such circumstances, the present inventors have conducted various studies on methods for easily utilizing active ingredients without using organic solvents, and as a result, they have found that cane molasses or glucose is used as a main carbon source in a beet molasses cation exchange resin adsorption eluent. It has been found that this method has the effect of significantly improving the fermentation yield of L-glutamic acid fermentation. The present invention was completed based on this knowledge. The method of the present invention can effectively utilize ion exchange resin desalination waste liquid, which has little utility value, generated in the process of producing beet sugar, as a cation exchange resin adsorption eluent, and thus L-glutamic acid can be economically advantageously produced. . The method of the present invention will be explained below. The medium used in the present invention is a conventional medium containing cane molasses or glucose as the main carbon source, a nitrogen source, inorganic salts, and, if necessary, organic micronutrients such as amino acids and vitamins.
As the nitrogen source, ammonium salts such as ammonium sulfate, ammonia, urea, etc. are used, and as the inorganic salts, phosphates, magnesium salts, iron salts, manganese salts, etc. are used. Various amino acids and vitamins such as biotin and thiamine are used as organic micronutrients. When glucose is used as a carbon source, biotin is added by a conventional method, and when cane molasses is used, since biotin is contained in excess, a nonionic surfactant such as polyoxyethylene sorbitan fatty acid ester or penicillin is added. An antibiotic is added as a biotin action inhibitor according to a conventional method. The cation exchange resin adsorption eluent for beet juice or beet molasses used in the present invention is diluted with water if the beet juice or beet molasses is needed, and is used in Amberline IR-120, IR-150, Dowex 50,
Resin eluted when regenerating the resin with acid after purifying the sugar solution by passing the liquid through or contacting a phenolic or non-phenolic strongly acidic cation exchange resin (H type) such as Dowex 30 or Diaion SK1B. An eluent is used. Further, since the ion exchange resin desalting waste liquid generated in the process of manufacturing beet sugar contains the cation exchange resin adsorption eluent, this desalting waste liquid can also be used. This method will be further explained. Beet juice (crude juice, raw juice) contains a large amount of inorganic salts in addition to sucrose, as well as colloidal substances such as protein and pectin, sugars such as raffinose and invert sugar, organic nitrogen content such as betaine and amino acids, oxalic acid, It contains many non-sugar components such as organic acids such as lactic acid, and these non-sugar components such as inorganic salts are harmful in sugar manufacturing.It is necessary to remove these harmful non-sugar components such as inorganic salts to increase the pure sugar rate and recover sucrose. Methods have been adopted to improve the rate. As a method for this, an ion exchange resin method has recently been adopted in place of the carbonate method, which has been used for a long time. This ion exchange resin method is also called the cold desalination method, and specifically, the crude juice cooled to 10 to 15°C is
The liquid is passed through a strongly acidic cation exchange resin (tower) in the form of OH to exchange cations with H ions, and the passed strong acidic sugar juice is passed through a weakly basic anion exchange resin in the OH form (tower) to exchange anions with OH ions. Replaced with pure sugar rate 97-98
This is a method to make % sugar juice. This method is used not only for purifying crude bead juice but also for recovering sucrose from blackstrap molasses in place of the so-called Stetsufen method. The cation and anion exchange resins that have adsorbed non-sugar content such as inorganic salts are regenerated with acid and alkali and used again. When the resin is regenerated, the adsorbed non-sugar content is eluted, and a large amount of this elution is produced as a so-called ion exchange resin desalting waste liquid. Of this resin waste liquid, only the eluent of the cation exchange resin has the effect of improving the L-glutamic acid fermentation yield, so it is desirable to select and use the adsorption eluent of the cation exchange resin. A resin-adsorbed eluent can also be used satisfactorily. The ion-exchange resin desalination waste liquid mainly contains inorganic salts, small amounts of organic acids, amino acids, and other organic nitrogen, and almost no sugar. It may be used as is, but it is concentrated to an appropriate concentration before use. The amount of culture medium added varies depending on the desalination process, etc., but in the case of desalinated waste liquid from beet molasses, an effect was observed in the range of 10 to 200 mg/dl relative to the culture medium in terms of total nitrogen, and 300 mg If more than /dl is added, the yield will actually decrease due to fermentation inhibition. The L-glutamic acid-producing bacteria used in the present invention are ordinary L-glutamic acid-producing bacteria, such as the following so-called coryneform L-glutamic acid-producing bacteria. Brevibacterium deivalicatum
ATCC 14020 Brevibacterium flavum ATCC 14067 Brevibacterium lactofermentum
ATCC 13869 Corynebacterium acetoacidophyllum
ATCC 13870 Corynebacterium glutamicum ATCC 13032 The culture method and the collection of L-glutamic acid from the fermentation solution can be carried out according to conventional methods, and no special methods are required. Examples will be described below. Example 1 An ion exchange resin desalination waste liquid produced in the molasses desalination process at a beet sugar factory in Hokkaido was concentrated to prepare a resin concentrate having a total nitrogen concentration of 0.6 g/dl, ash content of 3.5%, and total sugar content of 0.06%. This concentrated waste liquid was added to a medium with the composition shown in Table 1 containing cane molasses, starch saccharification solution, and a mixture of cane molasses and starch saccharification solution (mixing ratio 1:1) as carbon sources at a total nitrogen concentration of 0 to 300 mg/dl. to prepare a medium for L-glutamic acid production, and adjust the pH to 7.8.
After adjusting to 300 mg each into a 1.0 volume small fermenter, the mixture was heated at 115°C for 10 minutes to sterilize.

[Table] Brevibacterium lactofermentum ATCC 13869 obtained by culturing in each medium in advance
15 ml of the seed culture solution was inoculated, and aeration and stirring culture (1/4V.VM, 1100 rpm) was started at 31.5°C. During the cultivation period, the pH of the culture solution was maintained at 7.8 with ammonia gas, and when using cane molasses as the carbon source, use the cane molasses, when using the starch saccharified solution as the carbon source, use the starch saccharified solution, or a mixture of both. When used as a carbon source, a mixture of both was added and cultured while adjusting the sugar in the culture solution to 2 to 4 g/dl in terms of sucrose. Also, during the culture, when the absorbance at 562 nm of the 26-fold diluted culture solution reached 0.45, polyoxyethylene sorbitan monopalmitate was added.
Added 0.18g/dl. Culture was carried out in this manner, and when the sugar consumption rate was substantially reduced, the supply of sugar was stopped, and the culture was terminated in 28 to 37 hours.
The accumulated amount of L-glutamic acid in each culture solution was measured by a conventional method, and the sugar yield was determined. The results are shown in Table 2.

[Table] Example 2 In the beet juice desalination process (main stream desalination) at a beet sugar factory in Hokkaido, a cation exchange resin adsorption eluate and an anion exchange resin adsorption eluate were separately collected and concentrated. The solution was added to the culture medium containing cane molasses as a carbon source shown in Example 1 at a concentration of 100% in terms of total nitrogen.
mg/dl, and then in the same manner as in Example 1.
Glutamic acid fermentation was performed, and the accumulated amount of L-glutamic acid and the sugar yield were determined. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. A method for producing L-glutamic acid by culturing L-glutamic acid-producing bacteria in a nutrient medium containing cane molasses or glucose as the main carbon source, which comprises adsorbing beet juice or beet molasses with a cation exchange resin. A method for producing L-glutamic acid by a fermentation method, which comprises using a medium to which an eluent is added at a total nitrogen content of 10 to 200 mg/dl. 2. The fermentation method according to claim 1, characterized in that an ion exchange resin desalination waste liquid produced in the production process of beet sugar is used as a cation exchange resin adsorption eluent with a total nitrogen content of 10 to 200 mg/dl. A method for producing L-glutamic acid.