大肠杆菌
碳通量
生物合成
焊剂(冶金)
丙氨酸
发酵
代谢途径
化学
生物化学
效价
拉伤
代谢通量分析
代谢工程
生物
新陈代谢
遗传学
氨基酸
基因
生态学
有机化学
解剖
生态系统
抗体
作者
Haiyan Zhou,Wenqing Ding,Xi Zhang,Hong‐Yu Zhang,Zhong‐Ce Hu,Zhi‐Qiang Liu,Yu‐Guo Zheng
摘要
Abstract β‐Alanine is the only β‐amino acid in nature and one of the most important three‐carbon chemicals. This work was aimed to construct a non‐inducible β‐alanine producer with enhanced metabolic flux towards β‐alanine biosynthesis in Escherichia coli . First of all, the assembled E. coli endogenous promoters and 5′‐untranslated regions (PUTR) were screened to finely regulate the combinatorial expression of genes panD BS and aspB CG for an optimal flux match between two key pathways. Subsequently, additional copies of key genes ( panD BS K104S and ppc ) were chromosomally introduced into the host A1. On these bases, dynamical regulation of the gene thrA was performed to reduce the carbon flux directed in the competitive pathway. Finally, the β‐alanine titer reached 10.25 g/L by strain A14‐R15, 361.7% higher than that of the original strain. Under fed‐batch fermentation in a 5‐L fermentor, a titer of 57.13 g/L β‐alanine was achieved at 80 h. This is the highest titer of β‐alanine production ever reported using non‐inducible engineered E. coli . This metabolic modification strategy for optimal carbon flux distribution developed in this work could also be used for the production of various metabolic products.
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