Preparation and application of poly(N,N-dimethylacrylamide-co-acrylamide) and poly(N-isopropylacrylamide-co-acrylamide)/κ-Carrageenan hydrogels for immobilization of lipase

In the present of this study, two novel polymeric matrixes that are poly(N,N-dimethylacrylamide-co-acrylamide) and poly(N-isopropylacrylamideco-acrylamide)/kappa-Carrageenan was synthesized and applied for immobilization of lipase. For the immobilization of enzyme, two different immobilization procedures have been carried out via covalently binding and entrapment methods. On the free and immobilized enzymes activities, optimum pH, temperature, storage and thermal stability was investigated. The optimum temperature for free, covalently immobilized and entrapped enzymes was found to be 30,35 and 30 degrees C, respectively. Optimum pH for both free and immobilized enzymes was also observed at pH 8. Maximum reaction rate (V-max) and Michaelis-Menten constant (K-m) were determined for free and immobilized lipases. Furthermore, the reuse numbers of immobilized enzymes also studied. It was observed that after 40th use in 5 days, the retained activities for covalently immobilized and entrapped lipases were found as 39% and 22%, respectively. Storage and thermal stability of enzyme was also increased by as a result of immobilization procedures. (c) 2006 Elsevier B.V. All rights reserved.