利用改性载体固定化大肠杆菌产琥珀酸

Succinic acid production with immobilized cells of Escherichia coli on modified carrier

采用聚乙烯亚胺(PEI)和戊二醛(GA)对棉纤维进行化学修饰,考察了载体改性后的性能和对固定化大肠杆菌产丁二酸的影响。改性后的载体菌体负载量提高了63.3%。培养基中葡萄糖浓度为43 g/L,添加改性棉纤维120g/L,以MgCO3为缓冲盐,进行批式发酵,丁二酸浓度达到29.6 g/L,比未改性棉纤维提高了11.3%;丁二酸收率达到70.5%,比改性前提高了7.5%;丁二酸生产速率达到0.66 g/(L.h),比改性前提高了37.5%。对该材料固载的细胞进行7次重复批式发酵,丁二酸产量、转化率和产率没有下降趋势,具有一定的重复稳定性。

Immobilization of Escherichia coli on cotton fiber modified by polyethylenimine coating and glutaraldehyde crossing-linking for succinic acid production was investigated.Compared with unmodified cotton fiber,static cell adhesion increased by 63.3% after the carrier was modified by PEI and GA.When 43 g/L glucose was put in fermentation medium,120 g/L PEI-GA cotton fiber was added,and MgCO3was used as neutralizer in batch fermentation,concentration of scuccinic acid was 29.6 g/L,productivity was 0.66 g/（L.h）and yield was 70.5%,increased by 11.3%,37.5% and 7.5%,respectively.The batch fermentation of immobilized cells on PEI-GA cotton fiber was repeated seven times.The concentration of scuccinic acid,yield and productivity did not decrease.It suggested that PEI-GA cotton fiber as immobilization carrier was suitable for scuccinic acid production by Escherichia coli AFP111.