金属螯合载体固定重组腈水解酶

以琼脂粉为基质制备金属螯合载体,并用于固定重组腈水解酶。研究发现:制备金属螯合载体最合适的金属离子为Zn2+。当Zn2+离子浓度0.3 mol/L、给酶量15.6 mg/g、固定化pH 8.0、固定化温度40℃时,制得的固定化酶活性最高。固定化酶最适反应温度为50℃、最适反应pH为7.0。当扁桃腈浓度为10 mmol/L、反应1 h时,固定化酶最大产率为0.041 mmol/(g·h);在反应12 h时,产物e.e.值可达到99%以上。固定化酶重复使用8次以后,酶活力仍保持在45%。

Immobilization of recombinant nitrilase on metal chelating carriers

Metal chelating carrier with agar as the matrix was prepared and employed to recombinant nitrilase immobilization.Zn2+ was selected as suitable chelator.When the concentration of Zn2+ was 0.3 mol/L and enzyme load was 15.6 mg/g,the immobilized nitrilase showed a high activity at pH 8.0 and 40 ℃.The maximum conversion of mandelonitrile to(R)-(-)-mandelic acid by the immobilized nitrilase was observed at pH 7.0 and 50 ℃.When the substrate concentration was 10 mmol/L and the reaction time was 1 h,the conversion reached 70% with 99% e.e.after 12 h.After 8 recycles in batch operation,the activity remained at 45%.