Mass-Transfer Limitations for Immobilized Enzyme-Catalyzed Kinetic Resolution of Racemate in a Batch Reactor

The immobilized enzyme-catalyzed kinetic resolution of racemate in a batch reactor was studied theoretically. An exact solution was developed for a first-order reaction coupled with the intraparticle and external mass transfers. The time courses of substrate concentration and conversion as well as the purity and yield of the desired product were predicted by the exact solution, and the effects of the intraparticle and external mass-transfer resistances on the enzyme enantioselectivity were also quantitatively discussed. A simple approximate solution, taking into account the simultaneous reaction/external and intraparticle mass-transfer processes for the immobilized enzyme, was presented to predict the purity and yield of the desired product. For a competitive Michaelis−Menten kinetic resolution process, the effects of the competitive inhibitions of substrate and free water on the resolution process were analyzed by the orthogonal collocation method. The effectiveness factor and the effective enantiomeric ratio were predicted by the domain division method for the simplest case that the resolution process is at pseudo steady state and the inhibition effect of free water can be neglected.