BIOTECHNOLOGY - Inshyna N.M. - 2009

CHAPTER 5. INDUSTRIAL BIOTECHNOLOGY

Amino Acid Production

Globally, over 800,000 tonnes of Amino Acids are produced annually, with a market value exceeding $5 billion. On an industrial scale, amino acids are obtained either by extracting them from protein hydrolysates or as metabolic products of Bacteria belonging to Corynebacterium or Brevibacterium.

Living organisms contain more than 150 amino acids, 20 of which serve as the Structural components of Proteins. Examples of the Applications of Proteinogenic Amino Acids are given in Table 5.4.

Overall, 66% of amino acids are used in animal feed production, 31% in the food industry, and 3% in medicine, cosmetics, and chemical synthesis.

Class="center">Table 5.4

Applications of Amino Acids

The largest share of amino acid production (60% of the total volume) comprises the following amino acids: glutamic acid, methionine, lysine, and glycine. Annually, microbiological Methods yield 500,000 tonnes of glutamic acid and 180,000 tonnes of lysine worldwide.

Essential Amino Acids (lysine and methionine) are used as supplements in plant-based feeds. Animal proteins contain 7–9% lysine, whereas wheat proteins contain 3%. Adding 0.3% lysine to feed reduces feed costs by 20%. Calculations show that 1 tonne of lysine replaces 75 tonnes of grain, 5 tonnes of fishmeal, or 9 tonnes of soybean meal, resulting in an additional 10 tonnes of meat production. The primary producer of lysine is Corynebacterium glutamicum.

In Russia, an industrial microbial strain synthesizing threonine was developed based on E. coli. Supplementing plant feeds with threonine significantly increases farm animal productivity.

In the food industry, amino acids are used as flavoring and aromatic agents. Glycine has a sweet taste and is therefore added to soft beverages; it also exhibits bacteriostatic properties. Cysteine improves bread-baking processes and product quality. Glutamic acid serves as the basis for producing monosodium glutamate, which is used as a flavor enhancer in the manufacture of seasonings.

In medicine, amino acids are used to treat various conditions. Arginine combined with aspartic or glutamic acid, as well as K-Na-aspartate, is used in the treatment of liver diseases. Phenylalanine and dihydroxyphenylalanine are effective in treating Parkinson's disease. Cysteine protects the SH groups of Enzymes from oxidation and has a detoxifying effect. Polyamino acids are used to manufacture surgical suture Materials.

Amino acids serve as the basis for producing the sugar substitute aspartame (the methyl ester of L-aspartyl-L-phenylalanine). Aspartame is a dipeptide consisting of aspartic acid and phenylalanine. It is 150 times sweeter than glucose.

Another sugar substitute also contains amino acids. British biochemists isolated a protein from the fruits of the African shrub Dioscorephyllum cumminsii Diels that is 100,000 times sweeter than sugar. Introducing the Gene for this protein into E. coli Cells has made it possible to produce this sugar substitute microbiologically.