Carboxylesterase from Spodoptera Litura: Immobilization and use for the Degradation of Pesticides

The immobilization of carboxylesterase from Spodoptera Litura in mesoporus molecular sieves was studied in this paper. Two different types of mesoporous sieves (MCM-41, SBA-15) were initially used as enzyme support to compare the efficiency of immobilization. The outcome showed the maximum enzyme loadings, twice as many in MCM-41, are 0.0267 L/g in SBA-15 support. The most efficient pH value for immobilization was at 6.5 for both types of the support and the optimal immobilizing time was 2 h for SBA-15 and 4 h for MCM-41. Hence, the SBA-15 mesoporous support was determined as the enzyme immobilization matrix to continue the investigation because of its superior properties for enzyme immobilization. Then a series of characters of the free and immobilized Carboxylesterase were compared. As a result, the immobilized enzyme was substantiated to be obviously more stable than the free enzyme under the variant conditions. The experiments of pesticides degradation show that, relative to degradation in natural environment, immobilization enzyme had a higher ability to reduce the organic compounds with ester bonds.