Candida cylindracea Lipase-Catalyzed Synthesis of Retinyl and Oleyl Palmitates; Carbon Chain Length Dependence of Esterase Activity

Abstract

The ester activity of lipase from Candida cylindracea has been investigated in paraffin/water biphasic mixtures and in an aqueous ethanol solution. In the biphasic mixture with paraffin as an inert solvent, the equilibrium was found to be at approximately 75% esterification of palmitic acid and oleyl alcohol. Analysis was by a titrimetric assay. In a monophasic solvent of aqueous ethanol, more than 50% of retinol was converted into retinyl palmitate in 1 h. Analysis was by spectrofluorophotometry. Thus the Candida lipase can synthesize esters in the presence of a bulk water phase. The formation of the esters over the hydrolysis products is thought to be due to the partitioning of the hydrophobic reactants between the surface and interior of the organic phase. The esterase activity of the lipase has been determined against a range of 4 nitrophenyl alkanoates (carbon chain length 2-18) at pH 7 and 37ºC in Tris buffer. Maximum activity occurred with the butanoate ester. The Michaelis-Menten parameters were determined for this substrate in the presence and absence of butan-1-ol which inhibited the reaction. The range of these data illustrates the potential for using this enzyme for biocatalytic purposes.