Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
Key Laboratory of Guangxi Biorefinery, Nanning, 530003, Guangxi, China.
J Ind Microbiol Biotechnol. 2019 Jan;46(1):45-54. doi: 10.1007/s10295-018-2103-8. Epub 2018 Nov 16.
Corynebacterium glutamicum SNK 118 was metabolically engineered with improved L-arginine titer. Considering the crucial role of NADPH level in L-arginine production, pntAB (membrane-bound transhydrogenase) and ppnK (NAD kinase) were co-expressed to increase the intracellular NADPH pool. Expression of pntAB exhibited significant effects on NADPH supply and L-arginine synthesis. Furthermore, argR and farR, encoding arginine repressor ArgR and transcriptional regulator FarR, respectively, were removed from the genome of C. glutamicum. The competitive branch pathway gene ldh was also deleted. Eventually, an engineered C. glutamicum JML07 was obtained for L-arginine production. Fed-batch fermentation in 5-L bioreactor employing strain JML07 allowed production of 67.01 g LL-arginine with productivity of 0.89 g L h and yield of 0.35 g g glucose. This study provides a productive L-arginine fermentation strain and an effective cofactor manipulating strategy for promoting the biosynthesis of NADPH-dependent metabolites.
谷氨酸棒杆菌 SNK118 经代谢工程改造,提高了 L-精氨酸产量。考虑到 NADPH 水平在 L-精氨酸生产中的关键作用,共表达了 pntAB(膜结合转氢酶)和 pppnK(NAD 激酶)以增加细胞内 NADPH 池。pntAB 的表达对 NADPH 供应和 L-精氨酸合成有显著影响。此外,从谷氨酸棒杆菌基因组中去除了编码精氨酸阻遏物 ArgR 和转录调节剂 FarR 的 argR 和 farR。竞争性分支途径基因 ldh 也被删除。最终,获得了用于 L-精氨酸生产的工程化谷氨酸棒杆菌 JML07。在 5-L 生物反应器中进行补料分批发酵,使用菌株 JML07 可生产 67.01 g L-精氨酸,比生产率为 0.89 g L h,葡萄糖得率为 0.35 g g。本研究为 L-精氨酸发酵提供了一种高产菌株和一种有效的辅酶操纵策略,可促进 NADPH 依赖性代谢物的生物合成。