Selection of hydrophobic membranes in the lipase-catalyzed hydrolysis of olive oil

A hydrophobic membrane (HVHP, polyvinylidene difluoride) was selected out of HVHP, PTHK and PTGC (polysulfone) membranes to immobilize Candida rugosa lipase by physical adsorption in the hydrolysis of olive oil in a stirred diffusion cell. A previous model that assumed the Michaelis-Menten kinetics and Langmuir adsorption isotherm for the adsorbed lipase was used to interpret the variation of initial hydrolysis rates with enzyme and substrate concentrations. Replacing the aqueous phase by a fresh buffer, with or without containing partially deactivated lipases, during the reaction did not affect the enzyme activity for the adsorbed lipase. Moreover, the same enzyme performance was obtained when a fresh and a regenerated membrane was used as the carrier in the membrane reactor.