1. Glutamic acid can be produced by protein hydrolysis and synthesis, but fermentation is the main method to produce glutamic acid. The carbon source for the fermentation of glutamic acid is the hydrolyzed sugar or molasses of potato, corn, cassava starch, coconut starch and other starches, as well as acetic acid, liquid paraffin (C16 paraffin is the best) and other petrochemical products. The carbon source is used to form the carbon frame and energy nutrients in microbial cells and metabolites. Nitrogen source is ammonium salt, urea, etc. Nitrogen is the main element of cell protein and nucleic acid, and nitrogen is also the main element of glutamic acid amino acid in fermentation product. Other auxiliary materials are inorganic salts, vitamins, etc. For example, microorganisms need appropriate phosphorus concentration. Magnesium is an inorganic activator to stimulate the growth of bacteria, potassium salt promotes acid production, and corn syrup provides biotin and organic nitrogen sources. In addition, it also includes various promoters and additives. The production bacteria are Brevibacterium, Corynebacterium pekinensis, etc. In a large fermentation tank, aerate and stir for fermentation at a temperature of 30-34 ℃ and pH>7-8. After 30-40 hours of fermentation, remove bacteria, extract glutamic acid from the fermentation liquid, and then refine it into finished products. In the above process, isoelectric point method is used for extraction, and ion exchange method, hydrochloride method, direct concentration method (when acetic acid is used as raw material) can also be used. The product produced by fermentation is L-glutamic acid, the content of which is more than 98%. Each ton of glutamic acid consumes 4000kg of starch (80%) and 25kg of strain. The advantage of the synthesis method is that it does not consume grain, but the production process requires high pressure (about 20MPa) and high temperature (above 120 ℃). It uses toxic raw materials, and the equipment investment is twice as high as that of the fermentation method. The racemic glutamic acid obtained needs to be separated, and the production process is complex. According to the production of 1t 99% sodium glutamate (monosodium glutamate), 640kg acrylonitrile is consumed by the synthesis method. When the annual output is more than 5000t, the production cost is close to that of the fermentation method.
2. Fermentation
3. Chemical synthesis
4. This product is mainly produced by fermentation. With molasses or starch as raw materials, Corynebacterium glutamicum or Micrococcus or Arthrobacter glutamicum as the strain, and urea as the nitrogen source, the fermentation is carried out at 30~32 ℃. After the fermentation is completed, the fermentation liquid is separated from the cell. When the ph value is adjusted to 3.0 with hydrochloric acid, the isoelectric point extraction is carried out. After separation, the glutamic acid crystal is obtained. The glutamic acid in the mother liquor is extracted with 732 ion exchange resin, crystallized, and dried to obtain the finished product.
5. Tobacco: BU, 22; FC，21； Leptospira can be obtained by hydrolyzing animal and plant proteins, decoloring, concentrating and crystallizing them. It can also be made from sugar or starch by fermentation. The racemate can be synthesized from acrylonitrile.
It is made from starch or molasses through fermentation and purification. The strains used mainly include Micrococcus glutamicus, Corynebacterium, Brevibacterium, Microbacterium and Arthrobacter.
With gluten as raw material, L-glutamic acid is obtained by acid hydrolysis, and then L-glutamic acid hydrochloride is obtained by hydrochloric acid salinization. The crude product is obtained by neutralization reaction between L-glutamic acid hydrochloride and aniline, and then the product is filtered and dried.