Construction of an l-cysteine hyper-producing strain of <i>Escherichia coli</i> based on a balanced carbon and sulfur module strategy.

Bo Zhang; Kai Chen; Hui Yang; Zidan WU; Zhiqiang Liu; Yuguo Zheng

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Construction of an l-cysteine hyper-producing strain of Escherichia coli based on a balanced carbon and sulfur module strategy.

Author: Bo ZHANG ¹ ; Kai CHEN ¹ ; Hui YANG ¹ ; Zidan WU ¹ ; Zhiqiang LIU ¹ ; Yuguo ZHENG ¹
Author Information

1. The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
Publication Type:Journal Article
Keywords: biosynthesis pathway; coordinated gene expression; fermentation engineering; l-cysteine; metabolic engineering
MeSH: Escherichia coli/metabolism*; Cysteine/metabolism*; Bioreactors; Sulfur/metabolism*; Serine/metabolism*
From: Chinese Journal of Biotechnology 2022;38(12):4567-4586
CountryChina
Language:Chinese
Abstract: l-cysteine is an important sulfur-containing α-amino acid. It exhibits multiple physiological functions with diverse applications in pharmaceutical cosmetics and food industry. Here, a strategy of coordinated gene expression between carbon and sulfur modules in Escherichia coli was proposed and conducted for the production of l-cysteine. Initially, the titer of l-cysteine was improved to (0.38±0.02) g/L from zero by enhancing the biosynthesis of l-serine module (serA^f, serB and serC^Cg) and overexpression of CysB. Then, promotion of l-cysteine transporter, increased assimilation of sulfur, reduction or deletion of l-cysteine and l-serine degradation pathway and enhanced expression of cysE^f (encoding serine acetyltransferase) and cysB^St (encoding transcriptional dual regulator CysB) were achieved, resulting in an improved l-cysteine titer (3.82±0.01) g/L. Subsequently, expressions of cysM, nrdH, cysK and cysIJ genes that were involved in sulfur module were regulated synergistically with carbon module combined with utilization of sulfate and thiosulfate, resulting in a strain producing (4.17±0.07) g/L l-cysteine in flask shake and (11.94±0.1) g/L l-cysteine in 2 L bioreactor. Our results indicated that efficient biosynthesis of l-cysteine could be achieved by a proportional supply of sulfur and carbon in vivo. This study would facilitate the commercial bioproduction of l-cysteine.