Improvement of catalytic activity of lipase from Candida rugosa via sol-gel encapsulation in the presence of calix(aza)crown.

Lipase from Candida rugosa (CRL) was encapsulated within a chemically inert sol-gel support in the presence of calix(aza)crowns as the new additives. The catalytic activity of the encapsulated lipases was evaluated both in the hydrolysis of p-nitrophenyl palmitate (p-NPP) and the enantioselective hydrolysis of racemic Naproxen methyl ester. It has been observed that the percent activity yields of the calix(aza)crown based encapsulated lipases were higher than that of the free lipase. Improved enantioselectivity was observed with the calix(aza)crown-based encapsulated lipases as compared to encapsulated free lipase. The reaction of Naproxen methyl ester resulted in 48.4% conversion for 24h and 98% enantiomeric excess for the S-acid, corresponding to an E value of >300 (E=166 for the encapsulated free enzyme). Moreover, the encapsulated lipases were still retained about 18% of their conversion ratios after the sixth reuse in the enantioselective reaction.