AUTHOR=Zhang Hao , Liang Zhong , Zhao Ming , Ma Yanqin , Luo Zhengshan , Li Sha , Xu Hong 

TITLE=Metabolic Engineering of Escherichia coli for Ectoine Production With a Fermentation Strategy of Supplementing the Amino Donor

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2022.824859

DOI=10.3389/fbioe.2022.824859

ISSN=2296-4185

ABSTRACT=<p>Ectoine, an osmotic pressure-compensated solute, is used in the food, agriculture, medicine, and cosmetics industries due to its ability to protect macromolecules. In this study, an ectoine-producing variant of <italic>Escherichia coli</italic>, ET08, was genetically constructed by introducing the <italic>ectABC</italic> gene cluster and eliminating metabolic pathways involving lysine and pyruvate. Medium optimization enhanced ectoine production from 1.87 to 10.2 g/L. Analysis of the transcriptional levels revealed that supplementation with ammonium sulfate enhanced the metabolic flux towards the biosynthesis of ectoine. Furthermore, by optimizing the copy number of <italic>ectA</italic>, <italic>ectB</italic>, and <italic>ectC</italic>, the recombinant <italic>E. coli</italic> ET11 (<italic>ectA</italic>:<italic>ectB</italic>:<italic>ectC</italic> = 1:2:1) produced 12.9 g/L ectoine in the shake flask and 53.2 g/L ectoine in a fed-batch fermenter, representing the highest ectoine titer produced by <italic>E. coli</italic>, which has great industrial prospects.</p>