A process for the preparation of L-amino acids, in which the following steps are carried out, a) fermenting the desired L-amino acid-producing bacteria in which at least the glyA gene is attenuated, in particular by removal of the natural promoter, and optionally b) concentrating the desired product in the medium or in the cells of the bacteria and c) isolating the L-amino acid, and optionally bacteria in which further genes of the biosynthesis pathway of the desired L-amino acid are additionally amplified are employed, or bacteria in which the metabolic pathways which reduce the formation of the desired L-amino acid are at least partly eliminated are employed, and nucleotide sequences of the lacI-tac-5′glyA or lacI-tac-glyA unit.