Stabilization of α-glucosidase in organic solvents by immobilization on macroporous poly(GMA-co-EGDMA) with different surface characteristics

a-Glucosidase from baker's yeast was immobilized on macroporous copoly- mers of ethylene glycol dimethacrylate and glycidyl methacrylate, poly(GMA-co-EG- DMA), with various surface characteristics and pore sizes ranging from 44 nm to 270 nm. Immobilization was done by glutaraldehyde on the copolymer previously modified with 1,2-diaminoethane. The specific activity of the obtained immobilized enzyme varied from 27 to 81 U/g, depending on the employed copolymer. The half lives of the immobilized enzyme in cosolvents were influenced by the surface characteristics of the copolymer, ranging from 60 to 150 min in 35 %m ethanol and from 10 to 44 min in 45 %d imethyl sulphoxide (DMSO). The best stabilities were obtained when the enzyme was immobi- lized onto a copolymer having a pore size of 48 nm in methanol and 270 nm in DMSO.