Esterification of Lauric Acid Using Lipase Immobilized in the Micropores of a Hollow-Fiber Membrane

摘要

A porous anion-exchange hollow-fiber membrane was prepared by radiation-induced graft polymerization and chemical modification to immobilize lipase for enzymatic reaction in an organic solvent.The amount of anion-exchange group introduced to the porous hollow-fiber membrane was 2.5 mol/kg_(fiber).A lipase solution was allowed to permeate through the porous anion-exchange hollow-fiber membrane,and lipase molecules that adsorbed onto the grafted polymer brush were cross-linked with glutaraldehyde.The lipase was immobilized at a density of 0.14 kg_(lipase)/kg_(fiber),which was equivalent to a degree of multilayer binding of 20.Esterification was carried out by passing a solution of lauric acid and benzyl alcohol in anhydrous isooctane through the lipase-immobilized membrane,and lipase activity was determined.A reaction percentage of 50% was achieved at space velocity 68 h~(-1).The maximum immobilized lipase and native lipase activities were 8.9 and 0.38 mol/(h centre dot kg_(lipase) ),respectively.Thus,the activity of the immobilized lipase was 23.4 times higher than that of the native lipase.