The kinetics of the hydrolysis of corn oil in the presence of a lipase from Pseudomonas sp. immobilized within the walls of a hollow fiber reactor can be modeled in terms of a three-parameter rate expression. This rate expression consists of the product of a two-parameter rate expression for the hydrolysis reaction itself (which is of the general Michaelis-Menten form) and a first-order rate expression for deactivation of the enzyme. Optimum operating conditions correspond to 30 degrees C and buffer pH values of 7.0 during both immobilization of the enzyme and the hydrolysis reaction. Under these conditions, the total fatty acid concentration in the effluent oil stream for a fluid residence time of 4 h is approximately 1.6 M. This concentration corresponds to hydrolysis of approximately 50% of the glyceride bonds present in the feedstock corn oil. The fatty acid of primary interest in the effluent stream is linoleic acid.