The kinetics of enzymatic hydrolysis of rice bran oil in organic solvent (n-hexane) by free and immobilized Candida lipolytica lipase were investigated in a batch reactor. The n-hexane does not alter pH and temperature optima, but an increase in n-hexane concentration decreases the enzyme activity. The kinetic model proposed to describe the inhibitory effect of solvents on lipolysis was found to fit our data well. © 1994.