Altered Metabolic Flux due to Deletion of odhA causes l -Glutamate Overproduction in Corynebacterium glutamicum

l -Glutamate overproduction inCorynebacterium 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, andl -glutamate production. Here we show that a strain deleted forodhA and completely lacking ODHC activity producesl -glutamate as efficiently as the induced wild type (27.8 mmol/g [dry weight] of cells for theohdA 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 thatl -glutamate overproduction can be caused by the change in metabolic flux alone. Interestingly, thel -glutamate productivity of theodhA -deleted strain is increased about 10% by each of thel -glutamate-producing inductions, showing that the change in metabolic flux resulting from theodhA deletion and the inductions have additive effects onl -glutamate overproduction. Tween 40 was indicated to induce drastic metabolic change leading tol -glutamate overproduction in theodhA -deleted strain. Furthermore, optimizing the metabolic flux from 2-oxoglutarate tol -glutamate by tuning glutamate dehydrogenase activity increased thel -glutamate production of theodhA -deleted strain.