[Effect of PTS modifications on L-tryptophan production in Escherichia coli].

L-tryptophan, one of the aromatic amino acids, is widely used in the fields of medicine, food and feed additives. The phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) plays an important role in glucose transport and phosphorylation in Escherichia coli. PTS-mediated regulation dominates the carbohydrates' uptake and metabolism in E. coli. We constructed L-tryptophan-producing bacteria containing two typical PTS mutations (ptsHIcrrglf⁻ glk⁺ and ptsG⁻) by Red homologous recombination system, and studied in 50 L jar fermenter using fed-batch fermentation. Both PTS system mutants had a great impact on the biomass (increasing 47.0% and 17.6%, respectively), L-tryptophan production (increasing 25.9% and 9.4%, respectively), glucose conversion rate (increasing 26.5% and 17.4%, respectively) and byproduct acetic acid generation (slightly increased and decreased，respectively).