Mass-transfer limitations for immobilized enzyme-catalyzed kinetic resolution of racemate in a fixed-bed reactor

A mathematical model has been developed for immobilized enzyme‐catalyzed kinetic resolution of racemate in a fixed‐bed reactor in which the enzyme‐catalyzed reaction (the irreversible uni–uni competitive Michaelis–Menten kinetics is chosen as an example) was coupled with intraparticle diffusion, external mass transfer, and axial dispersion. The effects of mass‐transfer limitations, competitive inhibition of substrates, deactivation on the enzyme effective enantioselectivity, and the optical purity and yield of the desired product are examined quantitatively over a wide range of parameters using the orthogonal collocation method. For a first‐order reaction, an analytical solution is derived from the mathematical model for slab‐, cylindrical‐, and spherical‐enzyme supports. Based on the analytical solution for the steady‐state resolution process, a new concise formulation is presented to predict quantitatively the mass‐transfer limitations on enzyme effective enantioselectivity and optical purity and yield of the desired product for a continuous steady‐state kinetic resolution process in a fixed‐bed reactor. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 29–39, 2001.