Preparation and characterization of a novel 3D polymer support for the immobilization of cyclodextrin glucanotransferase and efficient biocatalytic synthesis of α-arbutin

In macropores of a melamine sponge epoxy resin was cured in ethanol solution. The produced polymer gel could uniformly deposit on the surface of melamine in either porous or nonporous morphology. The composite sponge with porous coating can be used as a large-sized and well-mass transferred support for the immobilization of cyclodextrin glucosyltransferase (CGTase, from Thermoanaerobacter sp.) through the method of adsorption and crosslinking, and a column reactor was made for the preparation of α-arbutin in a sealed circulation way. The porosity and specific surface area were 91.6 % and 46 m 2 /g, respectively. The loading amount and the specific activity of immobilized CGTase under the optimal immobilization conditions were 42 mg/g support and 651 U/g support , respectively. 5 mg/ml maltodextrin and 10 mM hydroquinone were used as a glucosyl donor and acceptor for the biosynthesis of α-arbutin, respectively. Under optimized conditions, the α-arbutin yield reached 61 % within 24 h at 40 °C. After 10 cycles, the immobilized CGTase retained 33 % of the α-arbutin yield.