Immobilization and characterization of β-galactosidase in thermally reversible hydrogel beads

Abstract

β-Galactosidase has been immobilized within thermally reversible hydrogel beads and has been studied in batch and packed bed reactor systems. The enzyme was entrapped in a copolymer hydrogel of N-isopropylacrylamide (NIPAAm) and acrylamide (AAm) as beads were formed in an inverse suspension polymerization. The optimum temperature for maximum activity of the immobilized enzyme-gel bead system was found to be 30-35°C in a batch mode and 40°C in a packed bed reactor, which were both below the 50°C optimum for the free enzyme. It was also found that when the operational temperature in the packed bed reactor was cycled between temperatures below (35°C) and above (45°C) the copolymer gel LCST, the activity of the immobilized enzyme almost fully recovered after each cycle.