Study on synthesis of a hydrophilic bead carrier containing epoxy groups and its properties for glucoamylase immobilization

A series of macroporous, hydrophilic and reactive bead carriers containing epoxy groups were synthesized by suspension polymerization of glycidyl methacrylate (GMA) and methacrylic acid (MAA), using divinyl benzene (DVB) as a crosslinking agent, while a mixture of linear poly(vinyl acetate) (PVAc) and toluene were used as pore-forming agents, meanwhile, the resulting carriers were employed in the immobilization of glucoamylase, i.e. glucoamylase be covalently immobilized because of the excellent reactivity of the epoxy groups in the carriers. The activity recovery of the immobilized glucoamylase could reach to 78%, the apparent Km value of the immobilized glucoamylase was about three times than that of the free ones, and the apparent Vmax value of the immobilized glucoamylase was slightly larger than that of the latter. For the hydrolysis of soluble starch using the resulting immobilized glucoamylase, the optimal pH and temperature were 5.0–6.0 and 55 °C, respectively. Otherwise, the immobilized glucoamylase exhibits excellent thermal stability, reusability and endurance property for acid and alkali.