Systems pathway engineering of Corynebacterium crenatum for improved L-arginine production.
Systems pathway engineering of Corynebacterium crenatum for improved L-arginine production.
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用于提高 L-精氨酸产量的锯齿棒杆菌系统途径工程
DOI：
10.1038/srep28629
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发表时间：
2016-06-24
影响因子：
4.6
通讯作者：
Xu Z
中科院分区：
文献类型：
--
作者：
Man Z;Xu M;Rao Z;Guo J;Yang T;Zhang X;Xu Z
L-精氨酸是一种重要的氨基酸，在食品和医药工业中具有重要的应用价值。目前，我国L-精氨酸的主要生产方法是高污染的角蛋白酸水解法。微生物发酵法生产L-精氨酸已成为工业化生产的重要课题。在前期工作中，我们通过筛选和诱变育种，获得了一株新的L-精氨酸产生菌钝齿棒杆菌（谷氨酸棒杆菌的亚种）。本工作中，我们进行了C. crenatum用于改善L-精氨酸生产，包括通过消除反馈抑制和精氨酸操纵子的过表达来放大L-精氨酸生物合成途径通量;通过调节糖酵解和戊糖磷酸途径之间的代谢通量分布来优化NADPH供应;通过加强预先存在的葡萄糖转运蛋白和开发新的葡萄糖摄取系统来增加葡萄糖消耗;将来自糖酵解的过量碳通量引导到三羧酸循环中以减轻葡萄糖溢出代谢;在α-酮戊二酸代谢节点处重新分配碳通量以将更多通量引导到L-精氨酸生物合成途径中;通过减弱副产物形成来最小化碳和辅因子损失。最终菌株在补料分批发酵中可以产生87.3 g L-1 L-精氨酸，产量高达0.431 g L-精氨酸g-1葡萄糖。
L-arginine is an important amino acid in food and pharmaceutical industries. Until now, the main production method of L-arginine in China is the highly polluting keratin acid hydrolysis. The industrial level L-arginine production by microbial fermentation has become an important task. In previous work, we obtained a new L-arginine producing Corynebacterium crenatum (subspecies of Corynebacterium glutamicum) through screening and mutation breeding. In this work, we performed systems pathway engineering of C. crenatum for improved L-arginine production, involving amplification of L-arginine biosynthetic pathway flux by removal of feedback inhibition and overexpression of arginine operon; optimization of NADPH supply by modulation of metabolic flux distribution between glycolysis and pentose phosphate pathway; increasing glucose consumption by strengthening the preexisting glucose transporter and exploitation of new glucose uptake system; channeling excess carbon flux from glycolysis into tricarboxylic acid cycle to alleviate the glucose overflow metabolism; redistribution of carbon flux at α-ketoglutarate metabolic node to channel more flux into L-arginine biosynthetic pathway; minimization of carbon and cofactor loss by attenuation of byproducts formation. The final strain could produce 87.3 g L−1 L-arginine with yield up to 0.431 g L-arginine g−1 glucose in fed-batch fermentation.