Preparation and properties of immobilized lipase supproted by porous chitosan membrane.

Abstract

Porous chitosan membrane was prepared by drying a mixed solution of chitosan and polyethylene glycol (PEG) in an oven at 50°C on a plate, followed by dialysis, and lipase was immobilized in the porous chitosan membrane with glutaraldehyde. The lipase immobilized in porous chitosan membrane obtained from the mixture of chitosan and PEG with the molecular weight of 20000 (1:1 in weight) had a high hydrolysis activity towards olive oil. The activity yield of the immobilized enzyme was as much as 64% of the native enzyme, and increased with decreasing membrane thickness. Much difference was found neither in pH nor temperature dependency between the activities of immobilized and native enzymes. The immobilized lipase in porous chitosan membrane retained about 180% of the activity at initial use after repeated use of 7 times.