title: [Effect of mufti-gene knockout of L-tryptophan transport system on L-tryptophan production in Escherichia coli].
abstract: In Escherichia coli, uptake of L-tryptophan is done by three distinct permeases, encoded by mtr, tnaB, and aroP. Based on the mtr single-gene knockout, we constructed the mtr.tnaB and mtr.aroP double-gene knockout mutants and the mtr.tnaB.aroP triple-gene knockout mutant. The fermentation results showed that the mtr.tnaB and mtr.aroP knockout mutants produced 1.38 g/L and 1.27 g/L L-tryptophan, respectively, which was 17% and 9% higher than that of the mtr knockout mutant. However, the mtr.tnaB.aroP knockout mutant was significantly affected on cell growth and only produced 0.63 g/L L-tryptophan. During the fed-batch fermentation in a 3-L fermentor, the mtr.tnaB knockout mutant produced 12.2 g/L L-tryptophan, which was 27% higher than that of the mtr knockout mutant. This study demonstrates the effect of multi-gene knockouts of L-tryptophan transport system of Escherichia coli on the biosynthesis of L-tryptophan.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Zhao
authors.forename: Sheng
authors.initials: S
authors.lastname: Chen
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D026905:Amino Acid Transport Systems / Q000235:genetics*; D001692:Biological Transport; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005285:Fermentation; D055786:Gene Knockout Techniques; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D014364:Tryptophan / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism
chemical_list: D026905:Amino Acid Transport Systems; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D050505:Mutant Proteins; C069255:mtr protein, E coli; D014364:Tryptophan