Here, Corynebacterium glutamicum SNK118 was metabolically engineered for L-ornithine production through CRISPR-Cpf1-based genome manipulation and plasmid-based heterologous overexpression. Genes argF, argR, and ncgl2228 were deleted to block the degradation of L-ornithine, eliminate the global transcriptional repression, and alleviate the competitive branch pathway, respectively. Overexpression of CsgapC (NADP-dependent glyceraldehyde 3-phosphate dehydrogenases gene from Clostridium saccharobutylicum DSM 13864) and BsrocG (NADH-dependent glutamate dehydrogenase gene from Bacillus subtilis HB-1) resulted markedly increased ornithine biosynthesis. Eventually, the engineered strain KBJ11 (SNK118ΔargRΔargFΔncgl2228/pXMJ19-CsgapC-BsrocG) was constructed for L-ornithine overproduction. In fed-batch fermentation, L-ornithine of 88.26 g/L with productivity of 1.23 g/L/h (over 72 h) and yield of 0.414 g/g glucose was achieved by strain KBJ11 in a 10-L bioreactor. Our result represents the highest titer and yield of L-ornithine production by microbial fermentation. This study suggests that heterologous expression of CsgapC and BsrocG could promote L-ornithine production by C. glutamicum strains.

中文翻译：

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CRISPR-Cpf1辅助的谷氨酸棒杆菌SNK118工程，用于通过NADP依赖性甘油醛3磷酸脱氢酶和NADH依赖性谷氨酸脱氢酶增强L-鸟氨酸的生产。

在这里，谷氨酸棒杆菌SNK118通过基于CRISPR-Cpf1的基因组操作和基于质粒的异源过表达进行了代谢改造，以生产L-鸟氨酸。删除了基因argF，argR和ncgl2228，以阻止L-鸟氨酸的降解，消除全局转录抑制并减轻竞争性分支途径。CsgapC（来自糖丁酸梭菌DSM 13864的NADP依赖性甘油醛3-磷酸脱氢酶基因）和BsrocG（来自枯草芽孢杆菌HB-1的NADH依赖性谷氨酸脱氢酶基因）的过表达导致鸟氨酸生物合成显着增加。最终，针对L-鸟氨酸的过量生产构建了工程菌株KBJ11（SNK118ΔargRΔargFΔncgl2228/ pXMJ19-CsgapC-BsrocG）。在分批补料发酵中，L-鸟氨酸为88。在10升生物反应器中通过KBJ11菌株获得了26 g / L的生产力（1.23 g / L / h（72小时））和0.414 g / g的葡萄糖产量。我们的结果代表了通过微生物发酵生产L-鸟氨酸的最高滴度和产量。这项研究表明，CsgapC和BsrocG的异源表达可以促进谷氨酸棒杆菌菌株生产L-鸟氨酸。