J. Plachý (Research Institute of Antibiotics and Biotransformations, Roztoky u Prahy, Czech Republic): Fermentation of amino acids. - Biologické listy 63 (1): 61-76, 1998.

At the present time, amino acids are produced by biotechnological methods based on the ability of microorganisms to synthetize amino acids at relatively high amounts, sufficient for a profitable industrial production. The majority of amino acids are now produced by fermentation, representing processes in which producing organisms, syntetizing L‑amino acids from simple raw materials, accumulate these compounds in a fermentation broth, from which they are isolated and purified. The most frequent amino acid producers are mutants of coryneform bacteria represented by the genera Corynebacterium and Brevibacterium. In addition to mutants of various type, obtained by mutation and selection (auxotrophic mutants, regulatory mutants, auxotrophic-regulatory mutants), the amino acid producers can be obtained by the methods of gene manipulation. The producers are able to synthetize amino acids from such carbon sources as sugar, ethanol or methanol under optimal conditions of aeration. These conditions can be very different for the individual amino acids. Amino acids overproduction is influenced by the mechanisms of metabolic regulations (on the level of both activity and expression) and amino acid secretion (as diffusion and carrier-mediated membrane transport). Amino acids produced by fermentations have made possible a broad application of amino acids, not only in medicine or as food and feed additives but also in the chemical industry. At the present time Japanese companies are chief amino acid producers in the world. Future trends concerning both the research domain and the amino acid application are discussed, too.