Preparation method
The amino acid manufactured from 1820 protein hydrolyzate. 1908 Japanese Ikeda sodium glutamate is a flavor enhancer, and began the history of the industrial production of amino acids. Japan began in 1957 with the use of microorganisms for glutamic acid fermentation, has since opened a new chapter in the history of the microbial fermentation production of amino acids. Around the 1960s, L-leucine biosynthesis and metabolic regulation mechanisms have been elucidated. For microbial fermentation production of targeted breeding and enzymatic production of L-leucine L-leucine provides a theoretical basis.
L-leucine production method of extraction, chemical synthesis, enzymatic method, microbial fermentation.
Protein hydrolysis
Amino acids are the constituent units of the protein, under acidic conditions, L-leucine-containing li a higher protein hydrolysis, a mixture of the various amino acids, L-leucine by the isolated, purified, refined processes products. Most of our manufacturers to adopt the the proteolysis production of L-leucine and L-cystine. The advantages of the protein hydrolysis method of producing L-leucine production equipment and technology not ask for much, and higher L-leucine in the protein content. However, the shortcomings of the production of protein hydrolysis is time-consuming, and cause serious pollution, low yield, product quality can not be guaranteed, mass production is limited.
Chemical synthesis
Leucine chemical synthesis A.Strecker, n halogenated acid, ammonia solution, and phase transfer catalysis are several ways. Although the principle of chemical synthesis method is simple, inexpensive, but the operation is complex, harsh reaction conditions, by-products, the production rate is not high, and some method related to toxic substances. The chemical synthesis of leucine is the racemic DL-leucine, L-leucine optical isomers must be split. Therefore, chemical synthesis method is rarely used in the production of L-leucine.
Enzymatic method
Enzymatic production of L-leucine is the use of transaminase aminotransferase to a keto-based dissidents gallic acid L-leucine and histidine-related and NADH covalently combined membrane, so that the substrate slowly to the membrane and the enzyme catalytic reaction of L-leucine. Such as 1981, Wichmann, er al. Established an ultrafiltration membrane made of membrane reactors, membrane covalent binding leucine transaminase, formic acid transaminase and NADH, when the substrate. Alien a keto acid through the membrane reactor can be catalyzed L-leucine, which NADH simultaneously by formic acid oxidation of C02 to achieve regeneration. The advantages of the enzymatic production of amino acids is the ability to transform, to avoid feedback inhibition in the metabolic regulation and feedback repressor, and the bioreactor is compact, relatively single product component, easy to carry out the process after processing, can improve product quality, reduce costs . The enzyme used in the enzymatic production of needs generated by microbial fermentation and extraction and purification process is more complex and higher cost, it has not yet been widely used. If low-cost access to high activity of the enzyme, the enzymatic production of L-leucine is an economically viable process route.