固定化柱状假丝酵母脂肪酶的制备与催化性能的研究

Preparation and Catalytic Property of Immobilized Candida cylindracea Lipase

通过反相悬浮技术制备了含磁性Fe3O4微粒的聚合物微球,利用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、红外光谱(FT-IR)、振动样品磁强计(VSM)和低温N2吸脱附等方法对微球进行了结构性质表征.结果表明,微球中Fe3O4质量分数为5.82%,比饱和磁化强度σs为3.85 emu/g,且具有超顺磁性;其比表面积、平均孔径和孔容分别为123.6 m2/g,13.01 nm和0.50 cm3/g,表面环氧基团含量为0.74 mmol/g.将磁性聚合物微球用于固定柱状假丝酵母脂肪酶,在30℃下用其催化(R,S)-2-溴丙酸甲酯不对称水解反应,产物(R)-2-溴丙酸的对映体过量值eep为17.7%,(S)-2-溴丙酸甲酯的对映体过量值ees为97.0%.固定化酶经5次重复使用,产物(S)-2-溴丙酸甲酯的对映体过量值ees值仍为75.7%,并且固定化酶在磁场的作用下能够快速沉降,与产物分离.

The polymer microspheres with Fe3O4 microcrystal were prepared via inverse suspension polymerization technology.Scanning electron microscopy（SEM）,FT-IR spectroscopy,X-ray diffraction（XRD）,vibrating sample magnetometer（VSM） and low temperature N2 adsorption were used to characterize the structure of the polymer.The results showed that the saturated magnetization of microsphere reached 3.85 emu/g while the Fe3O4 content were 5.82% and the microspheres were superparamagnetic.The specific surface area,average pore diameter,pore volume and oxirane content was 123.6m^2/g,13.1nm,0.3cm^3/g and 0.74mmol/g,respectively.Candida cylindracea lipase was immobilized on the magnetic polymer beads by covalent coupling and the immobilized lipase were applied for the asymmetrical hydrolysic of（R,S）-methyl 2-bromopropionate at 30℃.The results showed the ee valune of（S）-methyl 2-bromopropionate and（R）-2-bromopropionate reached 97% and 17.7%.The immobilized lipase also presented definite operation stability,the ee value of（S）-methyl 2-bromopropionate reached 75.5% after 5 baths and the immobilized lipase can be sedimentated quickly in the magnetic field and separated facilely from the product in applications.