乙烯基Ia3d介孔硅分子筛的环氧化及其固定化青霉素酰化酶(英文)

采用直接共聚法合成表面含有乙烯基的具有立方相Ia3d结构的介孔硅分子筛(V-ClMS),然后对乙烯基团进行环氧化制备得到表面环氧基功能化的介孔硅分子筛(E-CIMS),采用X射线衍射、N2吸附-脱附、透射电镜、热重分析和13C固体核磁共振对制备的介孔硅分子筛进行了表征.结果表明,表面含有乙烯基的V-ClMS介孔硅分子筛能被一步成功合成,并易于发生环氧化而获得表面环氧基功能化的E-CIMS介孔硅分子筛.将E-CIMS介孔硅分子筛作为载体用于固定化青霉素G酰化酶(PGA),研究了表面环氧基团对固定化PGA初活性和操作稳定性的影响.结果表明,随着表面环氧基团数量的增加,介孔硅分子筛孔径减小,表面疏水性增加,导致载酶量和初活性减小.但介孔硅分子筛表面适量的环氧基团能增强E-CIMS介孔硅分子筛与PGA之间的相互作用,从而提高固定化PGA的操作稳定性.

Epoxidation of vinyl functionalized cubic Ia3d mesoporous silica for immobilization of penicillin G acylase

Epoxy functionalized cubic Ia3d mesoporous silica (CIMS) was successfully synthesized by epoxidizing vinyl groups prepared on the CIMS by a co-condensation method. The synthesized material was characterized by X-ray diffraction, nitrogen sorption, transmission electron microscopy, thermogravimetric analysis, and solid state ¹³C NMR. The vinyl groups were found to be easily epoxidized to yield epoxy functionalized CIMS. The epoxy functionalized CIMS was used as a support for the immobilization of penicillin G acylase (PGA), and the effects of the epoxy group on the initial activity and the operational stability of the immobilized PGA were studied. The results showed that the enzyme loading and initial activity of the immobilized PGA decreased with increasing amounts of epoxy groups. These observations were due to a decrease in the pore size of the mesoporous silica as well as an increase in the hydrophobicity of the silica surface. However, an appropriate amount of epoxy groups on the CIMS support was found to improve the operational stability of the immobilized PGA. This improvement was the result of increased interactions between the epoxy functionalized CIMS support and the PGA.