基于关键酶表达的发酵调控与分子改造策略对E.coli产丁二酸的影响

考察E.coli JM001及其重组菌株E.coli JM002生物发酵生产丁二酸的性能。E.coli JM001在两阶段发酵产丁二酸过程中通过在有氧培养阶段添加乙酸钠,即可提高丁二酸的生产能力,厌氧阶段的丁二酸收率可达84%,但会有较多的副产物乙酸和丙酮酸积累。以E.coli JM001为出发菌株,敲除其磷酸烯醇式丙酮酸羧化酶(PPC)并导入来源于枯草芽孢杆菌的磷酸烯醇式丙酮酸羧化激酶(PCK)基因,构建了重组菌株E.coli JM002,该重组菌株在两阶段发酵的有氧培养过程中不需添加乙酸钠,转厌氧后菌株也具有转化葡萄糖合成丁二酸的能力,丁二酸收率可达86%,副产物积累很少。

Effects of fermentation regulation and molecular modification on succinate production by E.coli based key enzyme expression

Two strains including E.coli JM001 and its recombinant strain E.coli JM002 were investigated for the production of succinate.The new recombinant strain of E.coli JM002 was constructed by deletion of PPC gene and overexpression of PCK gene from B.subtilis 168 based on E.coli JM001.The ability of E.coli JM001 of producing succinate could be enhanced when growed aerobically on sodium acetate during dual phase fermentation,and the mass yield of succinate during anaerobic phase reached 84%.The acetate and the pyruvate were the main by-products.When dual phase fermentation with E.coli JM002 was conducted without adding acetate during aerobic phase,the glucose could be metabolized to succinate under anaerobic condition with a high yield of 86%,and little by-products(acetate and pyruvate) accumulated.