【摘要】 本研究采用3-丙氨基三乙氧基硅烷(APTES)和戊二醛修饰包裹有SiO2磁性Fe3O4纳米颗粒表面,将其作为固定化载体固定化乙醇脱氢酶,研究固定化条件对固定化效率的影响,并对固定化酶性质进行分析。研究发现,当Fe3O4@SiO2纳米颗粒修饰上氨基和醛基后依然具有良好的水分散性和胶体稳定性,适合作为固定化载体。通过单因素优化,发现当最适给酶量为11. 3U/100 mg,搅拌转速为150 r/min,固定化p H和固定化温度分别控制在6. 5和5℃～15℃,固定化时长为45 min时,具有较好的固定化效果,固定化率可达到60. 2%。在此条件下制备得到的固定化酶与游离酶相比,固定化酶具有良好的耐高温和耐碱性。所得固定化乙醇脱氢酶在连续使用8次后,固定化率仍保留在57%左右,表明该固定化酶具有较好的操作稳定性,可为连续生产NADH提供技术依据。更多还原

【Abstract】 The immobilization of alcohol dehydrogenase by magnetic Fe3 O4 nanoparticles surface modified with( 3-aminopropyl) triethoxysilane( APTES) and glutaraldehyde was studied,and the effects of the immobilization conditions on the immobilization efficiency were investigated. The results showed that Fe3 O4@ SiO2 nanoparticles modified with amino and aldehyde groups still kept great water dispersibility and colloidal stability,which could be used as the immobilization carrier. The optimum immobilized conditions were screed by single factor optimization,including the optimum amount of enzyme of 11. 3 U/100 mg,shaked speed of 150 r/min,the immobilized pH of 6. 5,immobilized temperature of 5 ℃ ～15 ℃ and immobilization time of 45 min. Under the optimum conditions,immobilization rate could reach 60. 2%.Compared with free enzyme,the immobilized enzyme had better temperature resistance and alkali resistance. The immobilization rate of the immobilized alcohol dehydrogenase still remained at about 57% after used for 8 times,which showed a great operating stability. This study could provide technical basis for continuous production of NADH.更多还原