SYNTHESIS OF N-OCTYL OLEATE WITH LIPASE FROM MUCOR-MIEHEI IMMOBILIZED ONTO POLYETHYLENE BASED GRAFT-COPOLYMERS

Lipase from Mucor miehei was immobilized onto partially hydrolyzed poly(ethylene)-g.co-hydroxyethyl methacrylate (PE/HEMA) via spacer arms of 1,6-diaminohexane and glutaraldehyde. The PE/HEMA-lipase system was used for the enzymatic esterification of n-octanol with oleic acid in the absence of organic solvents. The influence of lipase concentration, in the attachment solution, on the ester production profile and initial reaction rate was studied. It was found that very small amounts of lipase gave preparations which reached good degrees of conversion. The effect of the initial oleic acid concentration on that pseudo-first order reaction, as well as the presence of water in the reactional medium and the influence of temperature were evaluated. It was found that initial oleic acid concentrations lesser than 1.2 M did not inhibit the immobilized lipase activity; the presence of small amount of water (10-30 mul) solubilized in the reaction mixture (6.5 cm3) increased the lipase activity and a maximum of activity of the immobilized lipase preparation was found at 55-degrees-C. The operational stability of the preparation was determined at 37-degrees-C in a BSTR type reactor and a half-life time of three days for the immobilized lipase was obtained.