Biosynthesis of D-1, 2, 4-butanetriol from D-xylose by recombinant Escherichia coli

1, 2, 4-Butanetriol (BT) is an important organic synthetic intermediate. In this study, the metabolic network of Escherichia coli was reconstructed by heterogeneously expressing a keto acid decarboxylase (mdlC) from Pseudomonas putida ATCC12633 and a D-xylose dehydrogenase (xdh) from Caulobacter crescentus CB15, and knocking out xylA, yjhH and yagE which were the genes of xylose utilization pathway and intermediary metabolite pathway for D-1, 2, 4-butanetriol synthesis. The recombinant strain could synthesize D-1, 2, 4-butanetriol directly using D-xylose as precursor. Culture conditions such as temperature, medium volume, pH of fermentation broth were investigated at the titer of D-1, 2, 4-butanetriol of 3.96 g·L^-1 under suitable fermentation conditions. The relationship between glucose utilization and D-1, 2, 4-butanetriol synthesis was discussed. After modifying the phosphoenolpyruvate: sugar phosphotransferase system (PTS) by knocking out ptsG the reconstructed E.coli could utilize glucose and xylose simultaneously, leading to a higher D-1, 2, 4-butanetriol productivity.