title: Metabolic engineering of Escherichia coli for microbial production of L-methionine.
abstract: L-methionine has attracted a great deal of attention for its nutritional, pharmaceutical, and clinical applications. In this study, Escherichia coli W3110 was engineered via deletion of a negative transcriptional regulator MetJ and over-expression of homoserine O-succinyltransferase MetA together with efflux transporter YjeH, resulting in L-methionine overproduction which is up to 413.16 mg/L. The partial inactivation of the L-methionine import system MetD via disruption of metI made the engineered E. coli ΔmetJ ΔmetI/pTrcA*H more tolerant to high L-ethionine concentration and accumulated L-methionine to a level 43.65% higher than that of E. coli W3110 ΔmetJ/pTrcA*H. Furthermore, deletion of lysA, which blocks the lysine biosynthesis pathway, led to a further 8.5-fold increase in L-methionine titer of E. coli ΔmetJ ΔmetI ΔlysA/pTrcA*H. Finally, addition of Na2S2O3to the media led to an increase of fermentation titer of 11.45%. After optimization, constructed E. coli ΔmetJ ΔmetI ΔlysA/pTrcA*H was able to produce 9.75 g/L L-methionine with productivity of 0.20 g/L/h in a 5 L bioreactor. This novel metabolically tailored strain of E. coli provides an efficient platform for microbial production of L-methionine. Biotechnol. Bioeng. 2017;114: 843-851. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Huang
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Liu
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Li-Qun
authors.initials: LQ
authors.lastname: Jin
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Xiao-Ling
authors.initials: XL
authors.lastname: Tang
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Zhen-Yang
authors.initials: ZY
authors.lastname: Shen
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Huan-Huan
authors.initials: HH
authors.lastname: Yin
authors.affiliation: Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.|Engineering Research Center of Bioconversion and Bio-Purification, Ministry of Education, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.
authors.forename: Yu-Guo
authors.initials: YG
authors.lastname: Zheng
mesh_terms: D061249:Batch Cell Culture Techniques; D019149:Bioreactors / Q000382:microbiology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D055786:Gene Knockout Techniques; D008239:Lysine / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways; D008715:Methionine / Q000032:analysis / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D013912:Threonine / Q000378:metabolism
chemical_list: D013912:Threonine; D008715:Methionine; D008239:Lysine
keywords: Escherichia coli; L-methionine; Na2S2O3; W3110; competing pathway; import system