The present invention relates to a process for the production of L-amino acids by fermentation of recombinant microorganisms of the Enterobacteriaceae family, wherein a) the yfiD ORF and/or the pflB gene or nucleotide sequences coding for the gene products are overexpressed in the microorganisms producing the desired L-amino acid, and the microorganisms are cultured in a medium under conditions in which the desired L-amino acid is enriched in the medium or in the cells; and b) the desired L-amino acid is isolated, in a manner such that constituents of the fermentation broth and/or the biomass in its entirety or in portions (>0 to 100%) either remain in the isolated product or are completely removed.