Thermo-sensitive amphiphilic block copolymer poly (styrene-b-N-isopropylacrylamide) with switchable catalytic activity immobilizing pectinase

Pectinase was immobilized onto thermo-sensitive amphiphilic block copolymers poly(styrene-b-Nisopropylacrylamide) PS-b-poly(N-isopropylacrylamide) (PNIPAM) by covalent attachment. Biochemical studies have found that the stability of the PS-b-PNIPAM support is not impeded by the bound proteins despite that up to 242.5 mg of enzyme is immobilized per gram of carrier particles. The immobilized enzyme retained nearly 65% of its initial activity over 30 days, and the optimum temperature and pH also increased to the range of 60 similar to 70A degrees C and 4.0 similar to 6.0, respectively. The immobilized enzyme also exhibited great operational stability, and more than 60% residual activity was observed in the immobilized enzyme after 10 batch reactions. Moreover, the lower critical solution temperature of the PS-b-PNIPAM support could be switched on or off by a small change in solution temperature. Thus, the immobilized pectinase could be recovered and showed durable activity during the recycle process.