In this study, the kinetic behavior of alpha-chymotrypsin-immobilized, unif
orm poly(isopropylacrylamide) gel beads was investigated. The kinetic study
was performed by using a continuous reactor operated at steady-state condi
tions. In the experiments, substrate feed concentration, residence time, an
d reactor temperature were changed. The results were explained by a diffusi
on-reaction model developed for steady-state conditions. The effectiveness
factor and Thiele modulus values of the thermosensitive enzyme-gel system w
ere estimated at different temperatures by using an iterative procedure bas
ed on fourth order Runge-Kutta algorithm. The results indicated that the ov
erall hydrolysis rate was controlled by the substrate diffusion through the
gel matrix. A bending point was detected for the Thiele modulus at the low
er critical solution temperature (LCST) of the thermosensitive gel. The eff
ective diffusion coefficient of substrate and effectiveness factor decrease
d suddenly at LCST. The mass transfer process within the thermosensitive ca
rrier could be described in detail by the proposed model. The results of ou
r numerical procedure were also compared with an analytical approximate sol
ution available in the literature. The consistency between two different mo
del was reasonably good. (C) 1999 John Wiley & Sons, Inc.