基于sigma因子全局代谢扰动提高克雷伯肺炎杆菌的3-羟基丙酸产量

利用易错PCR技术构建了全局转录机器工程（gTME）关键元件σ因子（rpoD基因）的突变文库，连接至表达载体，电转化K.pneumoniae DSM 2026，并且从大量阳性克隆中筛选出一株3-羟基丙酸（3-HP）高产菌。初步发酵试验表明，该携带突变rpoD基因的工程菌能高效利用甘油生产3-HP，产量达到4.49g/L，比携带野生型rpoD基因的对照菌提高242.75%，甘油转化率、生产强度分别提高了832.50%、239.39%。

Metabolic perturbation of Klebsiella pneumoniae with a sigma factor for accumulation of 3-hydroxypropionic acid

The rpoD gene,encoding a sigma factor in Klebsiella pneumoniae,was cloned by the polymerase chain reaction(PCR) and its mutant library was constructed with an error-prone PCR method.Subsequent ligation to an expression vector and transformation into K.pneumoniae DSM 2026 led to plentiful positive clones.Of these,one recombinant was screened and fermented using glycerol as the sole source of carbon.Under the preliminary optimized conditions,this recombinant afforded a 3-hydroxypropionic acid yield of 4.49g/L.Compared with the control strain,it showed 242.75% increase in yield,and increases of 832.50% and 239.39% in glycerol conversion ratio and productivity,respectively.