Effects of external diffusion and design geometry on the performance of immobilized glucose isomerase reactor system

Using immobilized glucose isomerase, the effects of superficial velocity of the reaction solution flowing through a packed-bed reactor on the apparent kinetic constants of reversible reaction system were studied. The results showed that the apparent kinetic constants, both V_m″ and K_m″, of the forward reaction varied significantly as the superficial velocity is changed, whereas those of the reverse reaction varied only slightly. Using the kinetic data determined experimentally, computer simulation of the enzyme reactor performance was carried out, and the importance of the external mass transfer in the proximity of immobilized-enzyme particles was recognized. The reactor performance, expressed in terms of productivity, was examined as a function of the reactor height-to-diameter ratio, H/D. The productivity of the reactor system goes through a maximum value at a H/D ratio of about 1.6. and decreases as the H/D ratio increases. Theoretical analysis of the reaction kinetics of immobilized-enzyme system that has reversible reaction kinetics is also presented. The experimental results showed good agreement with the results found from the theoretical analysis and the computer simulation studies. Based on the principles of the methods and the results presented in this paper, it is anticipated that one can predict the optimal design and operating conditions for the glucose isomerase reactor system and that application of the results could be extended to other enzyme systems with reversible reaction kinetics.