Degussa Aktiengesellschaft

Evonik Degussa Gmbh

Nicole Siebelt

Mechthild Rieping

This invention relates to a process for the production of L-amino acids, in particular L-threonine, in which the following steps are performed: a) fermentation of microorganisms of the Enterobacteriaceae family which produce the desired L-amino acid, in which at least one or more of the genes, selected from the group iclR and fadR, or nucleotide sequences coding therefor, are enhanced, in particular overexpressed, b) accumulation of the desired L-amino acid in the medium or in the cells of the bacteria and c) isolation of the desired L-amino acid.

Process for the production of L-amino acids using strains of the Enterobacteriaceae family which contain an enhanced fadR or iclR gene

The invention relates to amino acid-producing bacteria from the family Enterobacteriaceae, in particular from the species, which contain a stop codon chosen from the group amber, ochre and opal in the nucleotide sequence for the coding region of the rpoS gene and a suppressor for a stop codon chosen from the group amber suppressor, ochre suppressor and opal suppressor. This invention also relates to a process for preparing amino acids, in particular L-threonine, using these bacteria.

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Rietberg, Germany

Nicole Siebelt