Microwave-Assisted Lipase Covalent Immobilization and Improved Its Thermal Stability Using Alcohols to Quench Excessive Activated Groups on Support Surface

Microwave irradiation technology is used to covalently immobilize lipase at low temperature to improve enzyme properties. The specific activity of lipase immobilized under microwave irradiation was 114.4 U·mg–1, 1.23 times of that for a traditional method without microwave irradiation. The Km and Kcat/Km of microwave immobilized lipase was 0.12 and 1.26 folds that of free lipase. Moreover, alcohols were used to quench the excessive activated groups on MCFs surface to improve thermal stability of immobilized lipase. Residual activity of immobilized lipase quenched by ethanol, retained 60.64% after incubation at 50°C for 5 h, 2.36 and 1.99 times higher than those of free lipase and immobilized lipase which was not quenched by alcohols, respectively. The results showed that microwave irradiation could improve lipase covalent immobilization and quenching remaining groups could enhance thermal stability of immobilized lipase.