FIELD: biotechnology, microbiology, amino acids. SUBSTANCE: non-proteinogenic amino acids are prepared by direct fermentation using the widely known strain of microorganism characterizing by the damaged regulation of cysteine metabolism that is carried out by the widely known method. This method differs from the known one by addition to fermentation medium in the process of fermentation of a nucleophilic compound that represents 1,2,3,4-tetrazolyl-L-alanine or its derivatives, or S-heteroaryl-L-cysteine. Using such nucleophilic compound taken in the definite amounts results to producing non-proteinogenic L-amino acids by the microorganism strain. EFFECT: improved preparing method. 18 cl, 11 ex
