Abstract
Lipases were coupled with polyethylene glycol with molecular weight of 5000. The modified lipases were soluble in organic solvents such as benzene, toluene and chlorinated hydrocarbons and exhibited high enzymic activity. The modified lipases catalyzed the reversed reaction of hydrolysis in organic solvents, ester synthesis and ester exchange reactions. These reactios also proceeded in hydrophobic substrates without organic solvents. Polyethylene glycol-modified lipase was conjugated with magnetite to form magnetic lipase. The magnetic lipase dispersed stably and catalyzed ester synthesis in organic solvents. Magnetic lipase particles could be readily recovered by magnetic force without loss of enzymic activity.