磁场条件下Fe^(2+)对产聚唾液酸大肠杆菌的诱变选育

Title Screening of high-yield polysialic acid producing Escherichia coli mutants induced by magnetic field combined with Fe^(2+)

以产聚唾液酸(polysialic acid,PSA)的大肠杆菌(Escherichia coli)为出发菌株,在磁场条件下利用Fe^(2+)对该菌种进行多轮诱变选育,获得具有高产性能的诱变菌株,在5L发酵罐进行发酵验证.结果表明:在0.5T磁场条件下,Fe^(2+)的最佳诱变质量浓度为90mg·L^(-1);经过5轮诱变和选育,PSA的摇瓶发酵水平从1.09g·L^(-1)提高到2.24g·L^(-1);5L发酵罐发酵水平从4.79g·L^(-1)提高到9.22g·L^(-1),产量提高了92%.

Compound mutagenesis using magnetic field and Fe 2＋ was carried out several rounds to gain a high-yielding Escherichia coli strain of polysialic acid （PSA） fermentation and the high-yielding strain was verified in 5 L fermentor. The results showed that the optimal Fe 2＋ ion concentration was 90 mg·L -1 in the compound mutagenesis using magnetic field of 0.5 T . The concentration of PSA in shaking flask fermentation in creased from 1.09 g·L -1 to 2.24 g·L -1 after five rounds of mutagesis, while the concentration of PSA in 5L fermentor fermentation raised from 4.79 g·L -1 to 9.22 g·L -1 , increased by 92%. Therefore, the compound mutagenesis of magnetic field and Fe 2＋ showed obvious effect on Escherichia coli of PSA fermentation.