Abstract: The current work aimed to investigate the molecular mechanisms of Tween-80 for triggering L-lysine
overproduction by Corynebacterium crenatum. L-lysine yield was increased by approximately 215% with the addition
of Tween-80 in C. crenatum. By using reverse translate real-time fluorescence quantitative polymerase chain reaction,
we determined that the transcriptional levels of odhA, sucB and lpdA, which encode three subunits of 2-oxoglutarate
dehydrogenase complex (ODHC), were up-regulated; pknG and dtsR1 involved in the signal transduction pathway for
ODHC regulation were up-regulated but ppp was down-regulated. As a result, ODHC-specific activity was increased by
32.9%. Furthermore, the transcriptional level of zwf involved in the pentose phosphate pathway was increased by 17.6
folds; thus, intracellular NADPH level was enhanced by 137% in C. crenatum triggered by Tween-80. The addition of
Tween-80 to the fermentation medium at the early exponential growth phase induced a bifunctional mechanism for L-lysine
overproduction by improving ODHC activity and NADPH supply in C. crenatum.

Key words: Corynebacterium crenatum, Tween-80, L-lysine, 2-oxoglutarate dehydrogenase complex, NADPH