The invention relates to a process for the preparation of L-amino acids,
in particular L-threonine, in which the following steps are carried out:
a) fermentation of microorganisms of the Enterobacteriaceae family which
produce the desired L-amino acid and in which the yjgF ORF or the
nucleotide sequence which codes for it are attenuated, in particular
eliminated, b) concentration of the L-amino acid in the medium or in the
cells of the bacteria, and optionally c) isolation of the L-amino acid.