Glutamic acid fermentation to about 15% of glucose as a carbon source, and add the appropriate amount of inorganic salts and biotin formulated into a fermentation medium, after the continuous elimination and cooled to 40 ℃ into the fermentation tank has been sterilized; to flow added liquid ammonia as a source of nitrogen, inoculated with the second level of expansion of the culture of the glutamic acid-producing bacteria.

Extraction is now generally used frozen isoelectric a ion exchange method. Fermentation solution in the isoelectric tank while using frozen brine slowly stirring cooling down to 5 ℃, while using sulfuric acid to adjust the Ph value to 3.22 (isoelectric point); precipitation 8h, precipitation by centrifugation to get the crude glutamic acid; mother liquor and the upper layer of the clear liquid after blending on the exchange of ion exchange resins, eluted with ammonia.

Pre-flow fraction converged into the upper layer of clear liquid re-column, post-flow fraction and ammonia together as eluent, high-flow fraction with the fermentation broth back to the isoelectric tank. Add glutamic acid to the neutralization tank containing bottom water at 60～65℃, stir, and slowly add soda ash solution, neutralize to Ph value 6.2～6.4, and control the concentration of the neutralization solution at relative density 1.1 7～1.18 (21～2 2°Bé).

When the neutralization solution cools down to below 50°C, appropriate amount of sodium sulfide solution is added to remove iron; then the Ph value is adjusted back to 6.2 to 6.4 with crude glutamic acid and warmed up to 60°C, and then powdered activated carbon is added, stirred for half an hour and then sent to the filter press for pressing and filtration.

The filtrate was then decolorized with granular activated carbon column for the second time to get clear liquid; the clear liquid was sent to the vacuum cooking pot at 60-70 ℃ evaporation and concentration to a relative density of 1.28 (31.5084), add 0.3 6-0.542mm crystal seeds and continue to evaporate and crystallize, during which the need for hot water to kill the crystals and replenish a certain amount of clear liquid.

After discharging, through the breeding crystal tank, and then centrifugal separation of crystalline monosodium glutamate, mother liquor or after decolorization and then evaporation and crystallization, refining yield up to 92% of the theoretical amount.

Expanded Information

1, flavoring agent

When used as a flavoring agent, the general dosage is 0.2% to 0.5%. In addition to use alone, it is appropriate to use with ribonucleotides and sodium inosinate and other nucleic acid flavoring materials with a composite flavoring to improve the effect. Monosodium glutamate is the most widely used at home and abroad, and salt *** storage can enhance its flavor, and 5'-inosinic acid sodium or 5'-guanosinic acid sodium used together, there is a multiplier effect.

Monosodium glutamate has a strong meat flavor, MSG diluted with water up to 3000 times can still feel the fresh flavor, widely used in the family, catering industry, food processing industry (soup, sausage, fish cake, hot sauce oil, canned food, etc.). Sodium guanosinate and monosodium glutamate used at the same time, has a synergistic effect, can improve the fresh flavor, also known as freshness aid or powerful monosodium glutamate.

2, pharmaceutical biochemical reagents

Glutamic acid is widely present in the organism of plants and animals, and is a naturally occurring nutrient component in food. After consumption, 96% of glutamic acid is absorbed in the body, and the rest is excreted in the urine after oxidation.

Although glutamic acid is not an essential amino acid, it can synthesize other amino acids in nitrogen metabolism with ketoacid amino transfer. Glutamic acid has the effect of reducing toxins in the blood. When liver function is impaired, the amount of ammonia in the blood increases, causing serious nitrogen metabolism disorders, leading to hepatic coma, and glutamic acid can work with ammonia to reduce the amount of ammonia in the blood.

In addition, brain tissue can only oxidize glutamate, but not other amino acids. When glucose is in short supply, glutamine acts as an energy source for brain tissue, so glutamate is necessary to improve and maintain brain function. In addition, it is used in medicine to prevent hepatic coma and to prevent epilepsy can also be used as a brain nutrient.

3, organic synthesis intermediates

In industry can be used as organic synthesis intermediates, but in the world's annual output, this use accounted for a very small proportion, such as the application of auxiliaries, osmotic membranes, silk protein modification, leather auxiliaries, biomedical materials, modified regeneration of collagen fibers and other various fields.

Reference source Baidu Encyclopedia - Monosodium Glutamate