Immobilization Of Lipase With Chitosan And Study Of Characterizations Of The Immobilized Lipase

Lipase from Proteus(LipaseA)has excellent organic solvent stability,which may render it promising for industrial application.Chitosan plays a very important role in the chemical industry of enzymatic immobilization due to its unique characteristics such as abundant sources,low prices and no poison.In the present study,two different forms of chitosan resin(microspheres and the amorphous powder)were prepared and used to immobilize lipase from Proteus.The influence on immobilization efficiency and the characterizations of immobilized lipase were analyzed.Our results showed that the immobilization efficiency of both microspheres particle resins and amorphous resins reached 67.5%and 61.7%respectively with 0.5%glutaraldehyde as crosslinking agent.The immobilization efficiency of both microsphere resins and amorphous resins reached the highest level of 77.2%and 68.3%respectively when the enzyme/support ratio of 15mg/g was applied.The immobized lipase is optimal active at 30? and pH 7.5.The pH stability of the immobilized enzyme was slightly improved while the thermal stability exhibited no significant difference between free enzyme and the immobilized one.The sesitivity of the immobilized lipase to organic solvents did not show obvious improvement compared to free enzyme but the immobilized lipase retained the excellent tolerance to organic solvents of free enzyme.After being used 25 times,the residual activity of immobilized enzyme on microsphere resins reached 89.6%while the residual activity of the immobilized enzyme on amorphous resins reached 87.3%after 15 times recycling uses,,indicating a good reusability of the immobilized enzyme.