MICROBIAL PRODUCTION OF L-LYSINE

Abstract

Seven homoserine, 42 methionine, 42 threonine and 15 isoleucine auxotrophs were obtained from B. flavum No. 2247 (ATCC No. 14067) by X-ray irradiation and N-methyl-N''-nitro-N-nitrosoguanidine treatment Concerning the L-lysine-producing ability, the homoserine auxotrophs were the best and about 1/2 of the threonine auxotrophs next The rest of threonine and all of the methionine and isoleucine auxotrophs produced little L-lysine. The L-lysine-producing threonine auxotrophs lacked homoserine kinase and accumulated the substrate, L-homoserine. The rest which produced little L-lysine and fairly much phosphohomo-serine lost the threonine synthase activity.