Effects of a feedback-resistant aspartokinase III gene on L-isoleucine production in Escherichia coli K-12

An L-isoleucine-overproducing recombinant strain of E. coli, TVD5, was also found to overproduce L-valine. The L-isoleucine productivity of TVD5 was m arkedly decreased by addition of L-lysine to the medium. Introduction of a gene encoding feedback-resistant aspartokinase III increased L-isoleucine p roductivity and decreased L-valine by-production. The resulting strain accu mulated 12 g/l L-isoleucine from 40 g/l glucose, and suppression of L-isole ucine productivity by L-lysine was relieved.