共表达甘油脱氢酶和二羟丙酮激酶对大肠杆菌生长及甘油代谢的影响

Effects on growth and glycerol metabolism in E.coli by coexpression protein GldA and DhaKLM

考察共表达甘油脱氢酶(GldA)和二羟丙酮激酶(DhaKLM)对大肠杆菌生长及甘油代谢的影响。结果表明:在好氧条件下,共表达甘油脱氢酶及二羟丙酮激酶可以提高大肠杆菌利用甘油合成菌体的效率,利用等量的甘油,重组菌最高菌密度比对照菌提高了70%,细胞干质量为3.54 g(以每升发酵液计)。在厌氧条件下,仅共表达甘油脱氢酶并不能促进大肠杆菌的甘油代谢,而同时共表达甘油脱氢酶和二羟丙酮激酶可以明显提高大肠杆菌代谢甘油的能力,每克菌体消耗的甘油量提高了42%,每克干细胞中达11.08 g,代谢产物组成也发生显著变化,乙酸成为主要产物。这说明共表达gldA及dhaKLM基因能有效促进大肠杆菌好氧利用甘油生长及厌氧甘油代谢的能力。

The effects on growth and glycerol metabolism in E. coli by overexpressing the glycerol dehydro- genase and dihydroxyacetone kinase were investigated. The results showed that coexpressing of glycerol dehydrogenase and dihydroxyacetone kinase could improve the efficiency of cell synthesis by 70% under recombinant E. coli under anaerobic condition and the dry cell weight（DCN） reached 3.54 g/L. Under anaerobic condition, only overexpressing glycerol dehydrogenase without dihydroxyacetone kinase could not improve the ability of glycerol metabolism in E. coli. However, the ability of glycerol metabolism was significantly improved by coexpressing glycerol dehydrogenase and dihydroxyacetone kinase in recombinant E. coli increased by 42% compared with the wild strain, and 11.08 g/g DCW glycerol was reached. Product composition of the recombinant changed by using acetate as the major product.