Lipase Nanogel Catalyzed Transesterification in Anhydrous Dimethyl Sulfoxide

Abstract

The present work showed that Candida rugosa lipase, which is inactive in anhydrous dimethyl sulfoxide (DMSO), has been granted its original catalytic activity and greatly enhanced stability when encapsulated into a polyacrylamide nanogel. The molecular simulation and structural analysis suggested that the polyacrylamide nanogel shielded the extraction of essential water and maintained the native configuration of encapsulated lipase in anhydrous DMSO at an elevated temperature. The electron and fluorescence microscopy showed that the lipase nanogel would be well dispersed in anhydrous DMSO where its native counterpart aggregated. The encapsulated lipase behaved as a stable catalyst for transesterification between dextran and vinyl decanoate in anhydrous DMSO at 60 degrees C for 240 h and yielded a dextran-based polymeric surfactant with regioselectivity toward the C-2 hydroxyl group in the glucopyranosyl unit of dextran. All these indicated a high potential of enzyme nanogel for nonaqueous biocatalysis.