Flux through the tetrahydrodipicolinate succinylase pathway is dispensablefor L-lysine production in Corynebacterium glutamicum

The N-succinyl-LL-diaminopimelate desuccinylase gene (dapE) in the four-ste p succinylase branch of the L-lysine biosynthetic pathway of Corynebacteriu m glutamicum was disrupted via marker-exchange mutagenesis to create a muta nt strain that uses only the onestep meso-diaminopimelate dehydrogenase bra nch to overproduce lysine. This mutant strain grew and utilized glucose fro m minimal medium at the same rate as the parental strain. In addition, the dapE(-) strain produced lysine at the same rate as its parent strain. Trans formation of the parental and dapE(-) strains with the amplified meso-diami nopimelate dehydrogenase gene (ddh) on a plasmid did not affect lysine prod uction in either strain, despite an eightfold amplification of the activity of the enzyme. These results indicate that the four-step succinylase pathw ay is dispensable for lysine overproduction in shake-flask culture. In addi tion, the one-step meso-diaminopimelate dehydrogenase pathway does not limi t lysine flux in Corynebacterium under these conditions.