增强海藻糖胞内积累提高大肠杆菌耐受性与乙醇产率

Enhanced intracellular trehalose accumulation improves stress tolerance and ethanol yield of Escherichia coli

为提高产乙醇大肠杆菌对发酵底物和乙醇的耐受性,并提高乙醇发酵性能,以大肠杆菌B0013-1031H为出发菌株,对其海藻糖代谢途径进行改造,获得了敲除海藻糖分解途径的突变株JC31和进一步加强海藻糖合成途径的突变株JC41。突变株JC31和JC41较出发菌株都具有更高的海藻糖合成与积累能力,其中JC41的胞内海藻糖含量可达出发菌株的12倍。与出发菌株相比,突变株JC31和JC41对葡萄糖和乙醇胁迫的耐受性显著提高。进一步引入乙醇合成途径,在葡萄糖质量浓度120 g/L的发酵条件下,菌株JC31-PA表现出最优的发酵性能,其最大乙醇产量为50.6 g/L,较对照菌株提高了5.42%;乙醇转化率为48.72 g/100 g葡萄糖,较对照提高了12.67%,达到理论转化率的95%。

In order to improve the tolerance of ethanologenic Escherichia coli to substrate and ethanol and the performance of ethanol fermentation,the trehalose metabolic pathway of E.coli B0013-1031H was engineered and the mutants JC31 and JC41 were constructed.In strain JC31,the trehalose catabolism pathways were deleted,the trehalose synthesis pathway was further enhanced and resulted in strain JC41.The ability of trehalose synthesis and accumulation of JC31 and JC41 was higher than that of the original strain,in which,JC41 intracellularly accumulated trehalose up to 12-fold that of the original strain.The tolerance of JC31 and JC41 to glucose and ethanol stress was significantly improved.The ethanologenic recombinant E.coli JC31-PA obtained by engineering ethanol synthesis pathway fermented 120 g/L of glucose and yielded 50.6 g/L of ethanol,which was 5.42%higher than that of the control strain.The conversion rate of ethanol from glucose was 48.72 g/100 g glucose,which was 12.67%higher than that of the control.