Production of L-lysine by alanine auxotrophs derived from AEC resistant mutant of Brevibacterium lactofermentum.

Relationships between L-lysine productivity and the formation of alanine in Brevibacterium lactofermentum were investigated. Alanine can be formed from pyruvate by transaminase with L-amino acid, and directly from aspartate in the presence of α-ketoglutarate and L-leucine. The later suggests that aspartate β-decarboxylase may contribute to the formation of L-alanine. However, this activity is approximately 1/20_??_1/50 of transaminase activity. Productivity of L-lysine was inversely as the level of pyruvate-L-amino acid transaminase. It was cofirmed by the derivation of alanine auxotrophs from AJ3445 (AECr). The best L-lysine producer, AJ3799, accumulated 39mg/ml of L-lysine and lacked pyruvate-L-amino acid transaminase.