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L(-)-Carnitine is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine. In living cells, it is required for the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids (fats) for the generation of metabolic energy.It is widely available as a nutritional supplement. L(-)-Carnitine was originally found as a growth factor for mealworms and labeled vitamin BT, although L(-)-Carnitine is not a proper vitamin. L(-)-Carnitine exists in two stereoisomers: Its biologically active form is L(-)-Carnitine, whereas its enantiomer, D-carnitine, is biologically inactive. After you ingest L(-)-Carnitine, it travels to your gut, and intestinal bacteria converts the L(-)-Carnitine into a substance called TMA, which then gets processed by the liver. The liver converts TMA into a compound that has been linked to plaque build-up in the arteries and heart disease. Red meat is one of the highest sources of L(-)-Carnitine, at about 56-162 mg per serving. L(-)-Carnitine can also be found in foods like pork, seafood, and chicken, but at much lower levels, between 3 and 7 mg per serving. Dairy, like ice cream, milk and cheese, has between 3 and 8 mg per serving. ( 1 ) Extraction. Naturally present in meat and dairy , so they can contain L- carnitine from beef and milk extracted directly . Reported in the literature , from 450g beef extract 0.6g crystals can be extracted L(-)-Carnitine, can be extracted from 56kg milk containing 2% L- carnitine lactose powder 100g. However, the cost of extraction is better economically not reasonable. ( 2 ) by microbial fermentation . Research shows that there are also many microorganisms L- carnitine, using yeast , Aspergillus , Penicillium , Rhizopus and other microorganisms in submerged culture or solid state fermentation , can accumulate L- carnitine. However, more complex screening of bacteria , the current is still relatively low level of fermentation . It is reported in 2% DL- carnitine as the raw material , 25 ? fermentation 44h, the accumulation of L- carnitine 0.4%. ( 3 ) synthesis. Alone in a foreign country in 1953 patented DL- carnitine synthesis reports, the 1960s have industrial production. As in 1982, there are domestic production and application of stomach . Directly from the DL- carnitine starting with camphor acid , N-acetyl -D- glutamic acid or ethylbenzene -L-(+) tartaric acid salt for chemical splitting get L- carnitine. However, D- carnitine racemic difficult can not be recycled , industrial production still need a breakthrough. ( 4 ) enzymatic conversion . This is the most studied , but also the final promising approach . Enzymes from microbial sources can be used for selective hydrolysis splits. Qing Zhongshan, Pseudomonas bacteria with amidase microorganism selective hydrolysis L(-)-Carnitine DL- carnitine amide or nitrile can be obtained an optical purity of 99 % or more of L- carnitine. In addition , you can also ß- dehydrogenation L(-)-Carnitine enzymatic conversion of trans crotonobetaine enzymatic hydrolysis and ?- butyl betaine enzymatic hydroxylation and other prepared L- carnitine. At present, only Switzerland, Italy, Japan and other countries students . Jiangsu Institute of Microbiology of enzymatic conversion is also carried out research .
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