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

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]-NH2 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]-NH2 and calix[6]-COOH based encapsulated lipases had higher conversion and enantioselectivity compared to the sol–gel free lipase.

The sol–gel encapsulation was carried out using calix[n]arene derivatives with different functional groups as addivities. The catalytic affect of sol–gel encapsulated lipases was investigated with the enantioselective hydrolysis reaction of racemic Naproxen methyl ester in aqueous buffer solution/isooctane reaction system. The results showed that the observed enantioselectivity and conversion of the particularly calix[4,6]-NH2 and calix[6]-COOH encapsulated lipases proved higher than that for the sol–gel free lipase.Figure optionsDownload as PowerPoint slide