Immobilization of α-amylase onto cyclic carbonate bearing hybrid material

Under ambient conditions, 4-((3-trimethoxysilyl)propoxy)methyl)1,3-dioxolan-2-one was synthesized from 3-glycidyloxypropyl trimethoxysilane. Methacrylate and cyclic carbonate functional hybrid matrix was prepared by sol-gel method. α-Amylase was covalently bounded onto the matrix via cyclic carbonate functionality. Immobilization yield was found as 34.4 ± 2.6 mg per gram of hybrid matrix. The maximum activity was observed at pH 6.5. Immobilization did not change the pH-dependency of the enzyme. The immobilized enzyme had a higher activity at elevated temperature (50–80° C) than the free one. Immobilized enzyme exhibited 80% activity after 20 runs and 69% after 30 runs. Free enzyme lost its activity completely within 15 days. Immobilized enzyme lost only 30% of its activity in 25 days. Vmax values for the free and immobilized enzymes were calculated as 58 × 10−3 and 5.2 × 10−3 mg/ml min−1, respectively.