关键词: 钝齿棒杆菌；L-精氨酸；吐温；还原型烟酰胺腺嘌呤二核苷酸；脂肪酸响应蛋白FarR

Abstract: The effect of Tweens (Tween 40, Tween 80, and Tween 80 combined with oleic acid) on in the metabolism of Corynebacterium crenatum MT NAGK M4 ΔproBΔNcgl1221ΔdtsR1 (CCM01) for L-arginine production was investigated by determining biomass concentration, L-arginine concentration and residual sugar levels in the fermented broth. Real-time polymerase chain reaction was used to evaluate the transcription levels of genes related to L-arginine biosynthesis. The results showed that addition of Tween 40, Tween 80, and Tween 80 combined with oleic acid increased the supply of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) and consequently the production of L-arginine. Notably, when Tween 80 and oleic acid were added to the medium at a molar ratio of 1:0.1, NADPH accumulation increased by 2.56 folds and L-arginine production increased by 29.43%. Additionally, the transcription levels of tkt-tal-zwf-opcA-pgl and gnd involved in NADPH biosynthesis were up-regulated, and the transcription level of the fatty acyl-responsive regulator FarR, a negative regulatory factor of arginine biosynthetic pathway, was down-regulated; accordingly, the transcription levels of gdh, argB and argG were up-regulated. The above results suggest that Tween can increase arginine production in two ways.

Key words: Corynebacterium crenatum; L-arginine; Tween; reduced nicotinamide-adenine dinucleotide phosphate; fatty acyl-responsive regulator