ZIF-8-戊二醛固定化细胞生产α-酮戊二酸

ZIF-8-glutaraldehyde-immobilized cells to produceα-ketoglutaric acid

为了提高表达L-谷氨酸氧化酶(LGOX)重组大肠杆菌的催化稳定性,本研究采用了沸石咪唑框架(ZIF-8)涂层和戊二醛(GA)交联的组合固定技术。确定了ZIF-8和GA的工艺参数以及固定化细胞的催化性能,并对固定化重组大肠杆菌催化L-谷氨酸生产α-酮戊二酸(α-KG)的稳定性展开了研究。当2-甲基咪唑、醋酸锌和戊二醛的添加量分别为240mmol/L、80mmol/L和50mmol/L时,固定化细胞(E.coli@ZIF-8-GA)的比活性和活性回收率分别达到33.4U/g和95.83%。结果表明,在重复使用10个批次后,E.coli@ZIF-8-GA转化生产α-酮戊二酸的产量仍能达到70.03g/L。与游离细胞相比,固定化细胞对温度和pH的耐受性均发生显著提高。

In order to improve the catalytic stability of recombinant Escherichia coli(E.coli)containing Lglutamate oxidase(LGOX),a combined immobilization technique of zeolite imidazole framework(ZIF-8)coating and glutaraldehyde(GA)cross-linking was used in this study.The process parameters of immobilized cells were determined and the stability ofα-ketoglutarate(α-KG)produced by immobilized cells was studied.The specific activity and activity recovery of immobilized cells(E.coli@ZIF-8-GA)were reached 33.4U/g and 95.83%,respectively,when 2-methylimidazole,zinc acetate and glutaraldehyde were added at 240mmol/L,80mmol/L,and 50mmol/L,respectively.The results showed that the yield ofα-KG could still reached 70.03g/L after reusing immobilized cells for 10 batches,which meant the stability of free cells in the reaction was enhanced.Compared with free cells,the tolerance to temperature and p H of immobilized cells was significantly improved,which laid a solid foundation for the application of immobilized catalyst to producingα-KG.