Alcoholysis of salicornia oil using free and covalently bound lipase onto chitosan beads

Porcine pancreatic lipase was immobilized on chitosan by covalent binding and retention of its activity was examined. The activities of free and immobilized lipase were determined using olive oil as substrate. The free and immobilized enzymes showed pH 9 as optimum and retained 50% of activity after five cycles. When the substrate concentration was kept constant and enzyme concentration was varied, the K-m and V-max were observed to be 4.0 x 10(-7) and 0.32, and 3.32 x 10(-7) and 0.32, respectively, for free and covalently bound enzyme. This indicates that there is no possibility of conformational change during immobilization. Immobilized enzyme showed improved thermal and storage stability. Alcoholysis of salicornia oil, mediated by free and immobilized lipase, was carried out at 25 degrees C using methanol in hexane and acetone. Free and immobilized enzyme in hexane produced, respectively, 45% and 55% of fatty acid methyl ester after 12 h. (c) 2005 Elsevier Ltd. All rights reserved.