The enzymatic hydrolysis of racemic ibuprofen ester by lipase from Candida rugosa using hollow fiber membrane reactor was studied. In process modeling and simulation of the enzymatic reaction in a horizontal hollow fiber membrane reactor system, two distinctive regions were studied: (i) diffusion in the fiber lumen; and (ii) reaction in the membrane matrix support. The model equations for both regions were developed and solved numerically by different approaches. In the first part, the modeling and simulation work was based on the diffusion of (S)-ibuprofen acid in which it leaves the reactor from the lumen side of the capillary fibers. The proposed mathematical model containing, non-linear partial differential equations was solved using the orthogonal collocation technique. The second part involved an enzymatic reaction taking place with the immobilized enzyme in the porous matrix support of the membrane, at which the substrate flows in from the shell side. The driving force was predominantly induced by pressure difference across the membrane where radial convection was the only mass transport in the porous support. The model was solved using two numerical techniques, the first technique based on the orthogonal collocation of weighted residuals in solving the non-linear partial differential equations of product diffusion in the capillary fibers; and the second technique was a collocation technique for solving ordinary differential equations (ODEs) of the enzymatic reaction in the porous support structure. The simulation was studied over a wide range of process parameters to investigate their effects on separation efficiency, in terms of enantiomeric excess, ee(S) and enantiomeric ratio, E, respectively. The model parameters include Peclet number, weight function parameters alpha, beta and collocation points (n), Thiele Modulus, Phi(2). dimensionless Michaelis constant, Theta and Bodenstein numbers, B-0. The performance of hollow fiber membrane reactor was found to be sufficiently effective at Theta = 0.55, B-0 = 0. 174 and ee(S) = 74% at Theta(2) < 1. (C) 2003 Elsevier Science B.V. All rights reserved.