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J Ind Microbiol Biotechnol. 2016 Sep;43(9):1227-35. doi: 10.1007/s10295-016-1803-1. Epub 2016 Jul 1.

Evolving the L-lysine high-producing strain of Escherichia coli using a newly developed high-throughput screening method.

Wang Y1,2,3, Li Q2,3, Zheng P4,5, Guo Y3, Wang L3, Zhang T1, Sun J6,7, Ma Y3.

Author information

1
College of Biotechnology, Tianjin University of Science and Technology, Tianjin, People's Republic of China.
2
Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
3
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
4
Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. zheng_p@tib.cas.cn.
5
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. zheng_p@tib.cas.cn.
6
Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. sun_jb@tib.cas.cn.
7
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. sun_jb@tib.cas.cn.

Abstract

This study provided a new method which applied a selected L-lysine-inducible promoter for evolving lysine industrial strains of E. coli. According to the intracellular levels of the enhanced green fluorescent protein (EGFP) whose expression was controlled by the promoter, 186 strains were preliminarily selected using fluorescence-activated cell sorting from a 10-million-mutant library generated from a L-lysine high-producing E. coli strain. By subsequent multiple parameter evaluation of the 186 selected strains according to the concentration and the yield of lysine, the productivity per unit of cell in 96-deep-well blocks, two mutants MU-1 and MU-2 were obtained. They produced 136.51 ± 1.55 and 133.2 9 ± 1.42 g/L of lysine, respectively, in 5-L jars. Compared with the lysine concentration and the yield of the original strain, those of strain MU-1 improved by 21.00 and 9.05 %, respectively, and those of strain MU-2 improved by 18.14 and 10.41 %, respectively. The mutant selection and evaluation system newly established in our study should be useful for continuous improvement of the current E. coli strains in the lysine industry.

KEYWORDS:

Escherichia coli; High-throughput screening; Lysine biosensor; Lysine production; Strain evolution

PMID:
27369765
PMCID:
PMC4983297
DOI:
10.1007/s10295-016-1803-1
[Indexed for MEDLINE]
Free PMC Article

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