Abstract: In transesterification experiment with lipase by two programs of transesterification, we found that in program I the transesterificaiton efficiency reached 90.15% while 52.51% in program II. Then we used diatomite and chitosan to immobilize lipase powder, followed by transesterification in program I. The methyl ester conversion rate of lipase immobilized with diatomite was higher than that with chitosan. Through the recycle transesterification experiment we found that the transesterification efficiency of lipase immobilized with diatomite and chitosan gradually reduced with the increase of cycling, in which the transesterification efficiency showed good correlation with hydrolysis activity．

Key words: transesterification, lipase, immobilization, biodiesel