Immobilization of invertase and glucoamylase on a macroporous copolymer of etyleneglycoldimethacrylate and glycidyl methacrylate and potential applications in biotechnology

Abstract

The optimal conditions for the immobilization of invertase and glucoamylasewere found via their carbohydrate moiety on a macroporous copolymer of ehtyleneglycoldimethacry late and glycidylmethacrylate. Almost all of the added enzyme was bound to the polymer by increasing the time of incubation of the oxidized enzyme with polymer. A specific activity of 5500 U/g for invertase was obtained and 1100 U/g for glucoamylase. The specific productivity for invertase in a packed bed reactor was 3.5 kg/lh and for glucoamylase 1.9 kg/lh. During continuous use in a packed bed the reactor operational half life for invertase was 290 days, while no decrease in activity was observed for glucoamylase. In 50% (v/v) ethanol the immobilized enzymes were five to ten times more stable, and more than 200 times more stable in 25% (v/v) dioxane. The immobilized enzymes retained all activity in petroleum ether after 3 days of incubation. Because of their higher stability over native enzymes, and the large surface area of the polymer immobilized glucoamylase and invertase could be more useful for glycoside synthesis in non-aqueous solvents than native ones.