Altered metabolic flux due to deletion of odhA causes L-glutamate overproduction in Corynebacterium glutamicum.
L-glutamate overproduction in Corynebacterium glutamicum, a biotin auxotroph, is induced by biotin limitation or by treatment with certain fatty acid ester surfactants or with penicillin. We have analyzed the relationship between the inductions, 2-oxoglutarate dehydrogenase complex (ODHC) activity, and L-glutamate production. Here we show that a strain deleted for odhA and completely lacking ODHC activity produces L-glutamate as efficiently as the induced wild type (27.8 mmol/g [dry weight] of cells for the ohdA deletion strain compared with only 1.0 mmol/g [dry weight] of cells for the uninduced wild type). This level of production is achieved without any induction or alteration in the fatty acid composition of the cells, showing that L-glutamate overproduction can be caused by the change in metabolic flux alone. Interestingly, the L-glutamate productivity of the odhA-deleted strain is increased about 10% by each of the L-glutamate-producing inductions, showing that the change in metabolic flux resulting from the odhA deletion and the inductions have additive effects on L-glutamate overproduction. Tween 40 was indicated to induce drastic metabolic change leading to L-glutamate overproduction in the odhA-deleted strain. Furthermore, optimizing the metabolic flux from 2-oxoglutarate to L-glutamate by tuning glutamate dehydrogenase activity increased the l-glutamate production of the odhA-deleted strain.
Asakura
Yoko
Y
Ajinomoto Co., Inc., Kawasaki, Kanagawa 210-8681, Japan. youko_kuwabara@ajinomoto.com
Kimura
Eiichiro
E
Usuda
Yoshihiro
Y
Kawahara
Yoshio
Y
Matsui
Kazuhiko
K
Osumi
Tsuyoshi
T
Nakamatsu
Tsuyoshi
T
D048230:Corynebacterium glutamicum / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005971:Glutamates / Q000096:biosynthesis*; D007655:Ketoglutarate Dehydrogenase Complex / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
D005971:Glutamates; D007655:Ketoglutarate Dehydrogenase Complex