以阳离子聚电解质聚烯丙基胺盐酸盐(PAAH)对共沉淀法制备的Fe3O4磁性纳米颗粒进行包裹,再以此对亚麻刺盘孢ColletotrichumliniST-1进行表面修饰,制备具有磁性的菌体复合物.通过SEM、XRD、VSM和zeta电位分析表明,PAAH修饰的Fe3O4能够稳定均一地结合在C.liniST-1菌体表面,形成的磁性复合物具有超顺磁性,可利用外加磁场对菌体进行回收.本研究利用该磁性复合物对去氢表雄酮(DHEA)进行生物羟化,制备三羟基雄甾烯酮(7α,15α-diOH-DHEA),通过回收菌体完成了4个批次的转化,产物7α,15α-diOH-DHEA的浓度为10.83g/L,约为游离菌体转化效果的3倍.%The cationic polyelectrolyte modified magnetic nanoparticles were prepared through surface modification of Fe3O4 nanoparticles that were prepared by co-precipitation method with poly (allylamine hydrochloride)(PAAH). The fungi of Colletotrichum lini ST-1 was then coated with the modified Fe3O4 nanoparticles to form magnetic composites. The magnetic composites were characterized by SEM,XRD,VSM,and zeta potential. The results demonstrated that the modified Fe3O4 nanoparticles adsorbed onto C. lini ST-1 cell surface stably and uniformly by electrostatic adsorption. The magnetic composites exhibited superparamagnetic properties, which could be utilized for strain recovery. During the biotransformation of dehydroepiandrosterone (DHEA)to 3β, 7α, 15α-trihydroxy-5-androsten-17-one ( 7α,15α-diOH-DHEA ), the magnetic composites could be recovered by the application of external magnetic field for 4 batches. The concentration of 7α, 15α-diOH-DHEA was 10.83g/L, which was about 3 times higher than that of the free cells.
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