Modification of lipase from Candida rugosa with poly(ethylene oxide-co-maleic anhydride) and its separation using aqueous two-phase partition system

摘要

A copolymer was synthesized from polyethylene oxide (PEO) and maleic acid anhydride (MA). Number of ethylene oxide units was varied from 10 to 40. Lipase from Candida rugosa was modified through chemical bonding of MA with amino group of lipase. Degree of modification increased with a decrease in EO unit and increase in co-polymer/enzyme ratio. The relative activity of modified en2yme increased with increase in EO unit. It was more than native lipase (100%) when copolymer/enzyme weight ratio was less than 3 for all copolymers. It might be due the conformation change of the lipase molecules on modification that would have exposed the catalytic sites making them more easily accessible. At the highest DM (39%), modified lipase retained more than 50% relative activity. Partitioning of native and modified lipase was also studied by using aqueous two phase synthesized copolymer/dextran system: modified lipase (with EO 30 and 40) showed better separation than the native one. Partition coefficient increased with increase in copolymer/enzyme weight ratio.