【摘要】 以吸附-絮凝耦合方法制备了微纳尺度的纳米TiO2-聚丙烯酰胺(polyacrylamide,PAM)杂化凝胶固定化酶.利用扫描电镜(SEM)、能谱面扫描(EDS)、粒度分析表征了杂化凝胶絮凝酶形貌、尺寸及分散性.通过对酸碱度有效调控,以及表面Zeta电位分析,探寻了酶-纳米复合凝胶静电作用机制.结果表明,静电相互作用力对酶的负载和颗粒粒度分布影响较大,在pH=7.0,TiO2和木瓜蛋白酶(papain,PA)质量比为7.5∶1时,固定化酶负载量达121.84 mg/g,负载率91.38%;杂化凝胶固定化酶尺寸约为0.444μm左右,固定化酶在杂化凝胶载体上高度分散.该杂化凝胶絮凝酶经过5批次反应后相对酶活力能保持在50%以上.可见由吸附-絮凝法制备的微纳尺度的杂化凝胶固定化酶,分散性好,稳定性好,酶负载量高,这是一种利用纳米材料和微纳结构进行固定化酶的新途径.更多还原

【Abstract】 The hybrid inorganic/organic gel with immobilized papain enzyme in micro/nano size was pre-pared by absorption-flocculation co-immobilization method,in which polyacrylamide(PAM) was used as the flocculation agent,and characterized by scanning electron microscopy(SEM),energy dispersive spec-trometer mapping(EDS),and size analyzer.Evolution of surface Zeta potential(ZP) of nano-gel containing enzyme with pH revealed that the main interaction between the enzyme and immobilization support was electrostatic attraction.The electrostatic field generated by the surface charges exhibited major impact on the enzyme loading and particle size distribution.At pH=7.0 and mass ratio of TiO2 to PA=7.5∶1,the maxi-mum amount of enzyme loading was achieved as 121.84 mg/g,corresponding to the efficiency of 91.38%.The size of nano-gel with immobilized enzyme was about 0.444 μm and its distribution was very narrow in either low or high pH range.SEM/EDS results showed that immobilized papain was homogeneously dis-persed in the porous hybrid gel.The stability test showed that the relative activity of immobilized papain still remained more than 50% even after five times cycle of reuse.It indicates that this novel method of immobi-lization could be propitious to the well dispersion,high stability and loading amount of papain.更多还原