中文摘要：

通过化学共沉淀法结合高锰酸钾氧化制备羧基化Fe3O4磁性微球,以该磁性微球作为载体,固定化谷氨酸脱羧酶。利用热重分析（TGA）、透射电镜（TEM）及振动样品磁强计（VSM）对羧基化磁性微球进行表征,结果表明该磁性微球磁含量约为95.1%,粒径均一,呈近似球形且具有超顺磁性。通过对固定化酶进行傅里叶红外光谱（FT-IR）、VSM和X射线衍射（XRD）分析,确定磁性微球载体与谷氨酸脱羧酶分子间形成酰胺键,实现共价结合且固定化酶前后粒子晶形完整,均具有良好的磁响应能力和超顺磁性。与游离谷氨酸脱羧酶相比,固定化酶的热稳定性和酸碱耐受性均有不同程度的提高,且制备的固定化酶重复使用10批后相对酶活力仍大于90%。

英文摘要：

Carboxyl Fe304 magnetic microspheres were prepared by a chemical co-precipitation method with potassium permanganate oxidation, and glutamate decarboxylase （GAD） was immobilized by the carboxyl magnetic microspheres as a carrier. The magnetic microspheres were characterized by methods of thermogravimetry （TGA）, transmission electron microscopy （TEM） and vibrating sample magnetometer （VSM）. The results indicated that the magnetic microspheres had 95.1% contents of magnetite, homogeneous size and superparamagnetic behavior. GAD was well wrapped up in the magnetic microspheres by Fourier transform infrared （FT-IR） analysis, VSM and X-ray diffraction （XRD）. The magnetic microspheres had complete crystal structure, good magnetic response and strong superparamagnetic behaviors before and after GAD immobilization. The enzymatic properties of immobilized and free GAD were analyzed and comoared. The results showed that immobilized GAD had better thermostability and pH resistance and retained more than 90% activity after ten repeated batches.