THERMAL CYCLING EFFECTS ON THE BIOREACTOR PERFORMANCES OF IMMOBILIZED BETA-GALACTOSIDASE IN TEMPERATURE-SENSITIVE HYDROGEL BEADS

The enzyme beta-galactosidase was immobilized in thermally reversible hydrogel beads that exhibit a reversible expansion and collapse of the gel volume in response to temperature. The kinetic performances of immobilized enzyme bead reactors were studied during thermal cycling operation. A periodic cycling of temperature for the packed-bed reactor induced a cyclic swelling and deswelling of the hydrogel beads. A temperature cycling operation around the phase transition temperature of the gel matrix enhanced the overall enzymatic conversion of the substrate, compared to its upper and lower isothermal operations. The effects on the overall conversion of various thermal cycling operational conditions, such as cycling range and heating and cooling rates, were investigated.