Process for the production of l-amino acids using enterobacterial family straines containing an intensified fadr gene.

A process for the production of L-amino acids selected from the group L-threonine, L-valine, L-homoserine and L-lysine, in which the following steps are carried out: a) fermentation of modified microorganisms of the Enterobacteriaceae family that produce the desired L-amino acid, where overexpression of the Escherichia coli fadR gene or nucleotide sequences encoding the fadR gene product leads to an increase of at least 10% of the activity or concentration of said fadR protein, in relation to to the activity or concentration of the protein in the starting microorganism, b) accumulation of the desired L-amino acid in the medium or in the cells of the microorganisms and c) isolation of the desired L-amino acid, where the constituents of the fermentation broth and / or the whole biomass or fractions thereof (> 0 to 100%) are optionally left in the product.