期刊
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
卷 44, 期 1, 页码 75-88出版社
SPRINGER HEIDELBERG
DOI: 10.1007/s10295-016-1870-3
关键词
Escherichia coli; L-homoserine; L-methionine; Metabolic engineering; Biosynthesis obstacle
资金
- National Natural Foundation of China [31401674]
- National High-Tech Research and Development Program of China (863 Program) [2011AA100905, 2012AA02120101]
- Science Found for Distinguished Young Scholars of Jiangsu province, China [BK20140002]
In this study, we constructed an l-methionine-producing recombinant strain from wild-type Escherichia coli W3110 by metabolic engineering. To enhance the carbon flux to methionine and derepression met regulon, thrBC, lysA, and metJ were deleted in turn. Methionine biosynthesis obstacles were overcome by overexpression of metA (Fbr) (Fbr, Feedback resistance), metB, and malY under control of promoter pN25. Recombinant strain growth and methionine production were further improved by attenuation of metK gene expression through replacing native promoter by metK84p. Blocking the threonine pathway by deletion of thrBC or thrC was compared. Deletion of thrC showed faster growth rate and higher methionine production. Finally, metE, metF, and metH were overexpressed to enhance methylation efficiency. Compared with the original strain E. coli W3110, the finally obtained Me05 (pETMA(Fbr)-B-Y/pKKmetH) improved methionine production from 0 to 0.65 and 5.62 g/L in a flask and a 15-L fermenter, respectively.
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