Preparation and properties of invertase immobilized on a poly(maleic anhydride-hexen-1) membrane

Poly(maleic anhydride-alt-hexen-1)(poly(MA-alt-H-1)) has been synthesized by radical polymerization and characterized by DSC, FT-IR, acid number determination, viscometric and NMR methods. Data showed that the co-polymer is an alternating co-polymer whose composition does not depend on the monomer feed composition. Invertase was immobilized onto a poly(MA-alt-H-1) membrane via glutaraldehyde and bovine serum albumin. The Km value of poly(MA-alt-H-1)-invertase was approximately 4.4-fold higher than the free enzyme, indicating decreased affinity by the invertase for its substrate (sucrose), whereas Vmax was lower for the immobilized invertase. Immobilization improved the pH stability of the enzyme, as well as its temperature stability. Immobilized samples obtained were stable and could be used many times over a period of 2 months without considerable activity loss.