Immobilization of lipase onto a photo-crosslinked polymer network: Characterization and polymerization applications

Abstract

The recovery of activity of lipases immobilized onto a photo-crosslinked polymer network was 76.0% and 41.0% for entrapment and adsorption methods, respectively. Both entrapped and adsorbed immobilized enzymes were very stable, retaining more than 60% of their activity over the range of temperatures studied. Immobilization by either method protected their relative activities nearly 96% at 70°C. The optimum pH was 8.0 for immobilized enzymes and 6.0 for the free enzyme at 40°C, while the relative activities after storage at 0–4°C for 30 days were 98% and 75% using entrapment and adsorption methods, respectively. These results indicated that lipase immobilized by entrapment and adsorption not only had good activity recovery, but also remarkable stability, better reusability and application adaptability than free lipase. Also, it can be safely stated that, photo-crosslinked polymer network can be used as alternative supports for immobilization of lipase for enzymatic polymerization reactions. In the ring-opening polymerization of ϵ-caprolactone, polymerization rates were clearly affected as monomer conversions were 58% and 49% and the highest molecular weights (Mn) obtained were 7890 and 5600 gmol− 1 for entrapment and adsorption methods, respectively.