| abstract |
The production of L-amino acid from the corresponding α-ketocarboxylic acid by bacterial fermentation in the presence of ammonium ions is carried out with the aid of thermophilic Bacillus strains at temperatures above 45 ° C., in particular above 60 ° C. Bacillus strains with the accession numbers DSM 406, 452, 461, 462, 463 as well as 465 and 466 are particularly suitable. The higher solubility of the amino acid at elevated temperature allows simple separation of the same from the reaction mixture by cooling, after which the depleted reaction mixture is in the fermenter can be pumped back. Acetate and / or glycerol and / or glucose are expediently used as energy-supplying co-substrates. Throttling the oxygen supply to the fermenter to values of less than 20% dissolved oxygen is beneficial. The process is particularly suitable for the production of valine, leucine, isoleucine, alanine and phenylalanine. |