Modeling enzyme immobilization in porous solid supports

Abstract

Enzymes are often immobilized on the internal surfaces of porous solid by immersing enzyme-free particles in a well mixed solution of enzyme. The ensuing impregnation process involves coupled transient mass transfer and surface attachment of enzyme. A mathematical model is employed to explore the influences of process parameters on the amount of enzyme loaded and the distribution of immobilized enzyme within the support particles. Nonuniform loading of the support occurs under some conditions. This is significant since the distribution of enzyme within the support particle influences the overall activity and stability of the immobilized enzyme catalyst. The model developed here may also be used to describe removal of reversibly immobilized enzyme during washing or utilization of the immobilized enzyme catalyst.

Modeling mass transfer and hydrodynamics in fluidized‐bed adsorption of proteins

“…A range of 0.5 X lo-' cm2/s to 2~ 10' cm2/s for S-HyperD LS was considered, since these values are consistent with those reported by other investigators for gel-filled chromatographic media (Weaver and Carta, 1996;Voute et al, 1996). For pore diffusion, the range varied from 0.5 X lo-' cm2/s, to 7 X cm2/s, and again this range was consistent with solid-diffusion coefficients reported for porous particles (Do et al, 1982;Pedersen et al, 1985;Yoshida et al, 1994;Weaver and Carta, 1996). As in previous cases, we have investigated the effect of solid diffusion coefficients as a function of mass-transfer mechanism and degree of bed expansion.…”

Enzyme adsorption in porous supports: Local thermodynamic equilibrium model

“…( 1 ) -(4), (6), (7), (9), and (10) are essentially the model of Do and co-workers. 16 In dimensionless form, eqs. (1)-(8) are reduced to be approximations to the corresponding derivatives at the locations xi that are the roots of an Nth-order Jacobi polynomial.…”

Distribution of immobilized enzymes on porous membranes

“…(8) and (9)]. The model of Hossain and Do considers an unstirred boundary layer to be contributing to the overall resistance to mass transfer.…”

“…The other difference between our theoretical approach and that of Hossain and Do is in the boundary conditions used at the interface between pore and bulk solutions [Eqs. (8) and (9)]. The model of Hossain and Do considers an unstirred boundary layer to be contributing to the overall resistance to mass transfer.…”