肺炎克雷伯氏菌3-羟基丙酸合成关键酶基因过表达与NAD^+再生的耦合

Coupling NAD^+ regeneration with overexpression of key enzymes for 3-hydroxypropionic acid biosynthesis in Klebsiella pneumoniae

在肺炎克雷伯氏菌(Klebsiella pneumoniae)中超表达内源甘油脱水酶基因dhaB和醛脱氢酶基因puuC,同时引入酿酒酵母(Saccharomyces cerevisiae)的3-磷酸甘油脱氢酶基因GPD1,得到耦合3-羟基丙酸(3-HP)合成与NAD+再生的重组菌K.p(pET-pk-dhaB-puuC-GPD1)。微氧摇瓶发酵结果显示在15h时3-HP产量达到1.45g/L,是携带空载体菌的2.39倍。分析是遗传扰动影响了底物甘油的代谢流量分配,从而提高了3-羟基丙酸的产量。

The glycerol dehydratase coding gene dhaB and the aldehyde dehydrogenase coding gene puuC from Klebsiella pneumoniae,and the 3-phosphoric acid glycerol dehydrogenase coding gene GPD1 from Saccharomyces cerevisiae,have been cloned by the polymerase chain reaction(PCR). Subsequently the recombinant K. pneumoniae K. p(pET-pk-dhaB-puuC-GPD1) was acquired. Under micro-oxygen fermentation conditions,it showed peak production of 3-hydroxypropionic acid(1. 45 g/ L) at 15 h,which is 2. 39 times that obtained with the strain harboring the blank plasmid pET-pk. These results suggest that overexpressing dhaB,puuC and GPD1 facilitates 3-HP biosynthesis via reallocation of the metabolic flux in K. pneumoniae.