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Biosynthesis of poly‐γ‐glutamic acid in Escherichia coli by heterologous expression of pgsBCAE operon from Bacillus
Author(s) -
Liu C.L.,
Dong H.G.,
Xue K.,
Yang W.,
Liu P.,
Cai D.,
Liu X.,
Yang Y.,
Bai Z.
Publication year - 2020
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.14552
Subject(s) - biosynthesis , operon , bacillus subtilis , escherichia coli , biochemistry , biology , plasmid , heterologous expression , heterologous , enzyme , gene , microbiology and biotechnology , bacteria , recombinant dna , genetics
Aims Poly‐γ‐glutamic acid (γ‐PGA) is an excellent water‐soluble biosynthesis material. To confirm the rate‐limiting steps of γ‐PGA biosynthesis pathway, we introduced a heterologous Bacillus strain pathway and employed an enzyme‐modulated dismemberment strategy in Escherichia coli . Methods and Results In this study, we heterologously introduced the γ‐PGA biosynthesis pathway of two laboratory‐preserved strains— Bacillus amyloliquefaciens FZB42 and Bacillus subtilis 168 into E. coli , and compared their γ‐PGA production levels. Next, by changing the plasmid copy numbers and supplying sodium glutamate, we explored the effects of gene expression levels and concentrations of the substrate l ‐glutamic acid on γ‐PGA production. We finally employed a two‐plasmid induction system using an enzyme‐modulated dismemberment of pgsBCAE operon to confirm the rate‐limiting genes of the γ‐PGA biosynthesis pathway. Conclusion Through heterologously over‐expressing the genes of the γ‐PGA biosynthesis pathway and exploring gene expression levels, we produced 0·77 g l −1 γ‐PGA in strain RSF‐EBCAE(BS). We also confirmed that the rate‐limiting genes of the γ‐PGA biosynthesis pathway were pgsB and pgsC . Significance and Impact of the Study This work is beneficial to increase γ‐PGA production and study the mechanism of γ‐PGA biosynthesis enzymes.