文献类型：期刊文献

英文题名：Multistep construction of metabolically engineered Escherichia coli for enhanced cytidine biosynthesis

作者：Yang, Kang[1];Li, Zhimin[1,2]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, 130 Meilong Rd, Shanghai 200237, Peoples R China;[2]Shanghai Collaborat Innovat Ctr Biomfg Technol, 130 Meilong Rd, Shanghai 200237, Peoples R China

年份：2020

卷号：154

外文期刊名：BIOCHEMICAL ENGINEERING JOURNAL

收录：;EI(收录号：20194607691837);WOS:【SCI-EXPANDED(收录号:WOS:000518148400011)】；

基金：This work was supported by the Fundamental Research Funds for the Central Universities (22221818014).

语种：英文

外文关键词：Cytidine; UMP; Metabolic flux; Metabolic engineering; Escherichia coli

摘要：As a kind of pyrimidine nucleoside, cytidine has been widely recognized as an important precursor for the production of some antiviral and antitumor drugs. In this study, the systematic construction of metabolically engineered Escherichia coli strain for cytidine over-production was investigated, where the regulation of downstream pathway from uridine monophosphate (UMP) toward cytidine was focused on. Firstly, the engineered strain CR016 obtained by deleting the cytidine catabolism-related genes in E. coli. MG1655 showed a significantly slower degradation rate of cytidine. Further modifications were carried out to amplify the metabolic flux from UMP to cytidine. The resulted strain CR023(pTrc03) began to accumulate 352.59 mg/L of cytidine in shake flask culture for 36 h. After optimizing the supply of three precursors, the final engineered strain CR023(pTrc03/pBAD021) produced 704.19 mg/L of cytidine with a yield of 0.15 g/g glucose, upon the supplementation with 2 mM glutamate. A fed-batch fermentation was then performed in a 5-L reactor to increase cytidine titer by 11.13-fold to 7.84 g/L in 48 h. The multistep metabolic engineering strategies presented here enabled a stepwise increase in the production of cytidine.