Genetic Transformation In Corynebacterium Glutamicum For Overproduaction Some Bioapplicable Amino Acids

Abstract

Amino acids are the building blocks of the life, and are long played an important role in both human and animal nutrition and health maintenance (Bercovici and Fuller, 1995). On account of its functionality and the special features arising from chirality, this class of compounds is biochemically extremely important and of great interest for the chemical industry (Leuchtenberger, 1996). Of the 20 standard protein amino acids, the 9 essential amino acids-L-valine, L-leucine, L-isoleucine, L-lysine, L-threonine, L-methionine, L­ histidine, L-phenylalanine, and L-tryptophan occupy a key position in that they are not synthesized in animals and humans but must be ingested with feed or food. In terms of market volume, development over the last 20 years has been tremendously bullish in the so-called feed amino acids L-lysine, L-methionine, L-threonine, and L-tryptophan, which constitute the largest share (56%) of the total amino acid market, estimated in 2004 at approximately US $4.5 billion (Fig. 1). Also substantial is the share of the food sector, which is determined essentially by three amino acids: L-glutamic acid in the form of the flavor enhancer monosodium glutamate (MSG) and the amino acids L-aspartic acid and L­ phenylalanine, both of which are starting materials for the peptide sweetener L-aspartyl Lphenylalanyl methyl ester (Aspartame), used, for example, in "lite" colas. The remaining proteinogenic amino acids are required in the pharmaceutical and cosmetics industries and are also ideal raw materials for synthesis of chiral active ingredients, which in turn find application in such sectors as pharmaceuticals, cosmetics, and agriculture. According to a study by the Business Communication Company (Brown, 2005), the amino acid market for synthesis applications is growing at an annual rate of 7% and is expected to reach a volume of US $1 billion in the year 2009, of which the share of amino acids for peptide sweeteners alone is expected to be more than US $400 million.