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

Lipase from Mucor miehei was immobilized onto partially hydrolyzed pol y(ethylene)-g.co-hydroxyethyl methacrylate (PE/HEMA) via spacer arms o f 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 init ial reaction rate was studied. It was found that very small amounts of lipase gave preparations which reached good degrees of conversion. Th e effect of the initial oleic acid concentration on that pseudo-first order reaction, as well as the presence of water in the reactional med ium and the influence of temperature were evaluated. It was found that initial oleic acid concentrations lesser than 1.2 M did not inhibit t he immobilized lipase activity; the presence of small amount of water (10-30 mul) solubilized in the reaction mixture (6.5 cm3) increased th e lipase activity and a maximum of activity of the immobilized lipase preparation was found at 55-degrees-C. The operational stability of th e preparation was determined at 37-degrees-C in a BSTR type reactor an d a half-life time of three days for the immobilized lipase was obtain ed.