Enantioselective hydrolysis of (R/S)-Naproxen methyl ester with sol–gel encapculated lipase in presence of calix[ n]arene derivatives

Abstract

Lipases are enzymes that catalyses a variety of reactions, such esterifications, interesterification and hydrolysis. Several methods have been reported for the immobilization of lipases, such as deposition onto solid supports, covalent binding and encapsulation within a polymer matrix or silica glasses obtained by sol–gel techniques. In this study, the Candida rugosa lipase was encapsulated within a chemically inert sol–gel support prepared by polycondensation by tetraetoxysilane (TEOS) and octyltrietoxysilane (OTES) in the presence and absence of calix[ n]arene, calix[ n]- NH 2 and calix[ n]- COOH ( n = 4, 6, 8) compounds as additives. The catalytic activity of the encapsulated lipases was evaluated into model reactions, i.e. the hydrolysis of p-nitrophenylpalmitate ( p-NPP), and the enantioselective hydrolysis of rasemic Naproxen methyl ester that was studied in aqueous buffer solution/isooctane reaction system. The results indicated that the particularly calix[4,6]- NH 2 and calix[6]- COOH based encapsulated lipases had higher conversion and enantioselectivity compared to the sol–gel free lipase.