Diffusion resistance and enzyme activity decay in a pellet

Abstract

The effective enzyme activity decay can be decreased by diffusion limitation in the immobilized pellet. Thiele modulus changes and/or poisoning of various enzyme forms are two phenomena which are influenced by diffusion limitation. This article considers these effects on enzyme decay as applied to glucose isomerase.

Generalized linearization of kinetics of glucose isomerization to fructose by immobilized glucose isomerase

“…Column performance is affected by thermal inactivaton of the enzyme (Illanes et al, 1996;van den Tweel et al, 1993) and diffusion resistance (Chen and Chang, 1984), whereas the presence of substrate proves to protect the enzyme, probably by stabilization of the activated complex tertiary structure induced by the link between active site and glucose (Verhoff and Goldstein, 1982). The conventional reversible Briggs-Haldane mechanism proves to be the best approach to describe isomerization kinetics, coupled with the activity decrease of the complexed GI, in both suspended (Roels, 1983) and immobilized systems (Chen and Wu, 1987), in either the presence or absence of substrate Del Borghi, 1997, 1998).…”

Immobilization of Biological Catalysts

“…The suitability of any of these methods for the application of biological catalysts in synthetic reactions depends on a variety of factors including the nature of the catalyst, the participating reactants and process conditions, and all the micro-environmental effects and limitations in mass transfer resulting from the transformation of a dissolved to a solid or solid-like catalyst. Indirectly, the activity and stability of an immobilized biocatalyst can be influenced by the density of active sites [6], the occlusion of active sites in the complex [7], the prohibition of conformational changes of biocatalysts [8], restrictions of the spatial rotation of substrates [9], partitioning effects, and mass transfer limitations [6,10]. Indirectly, the activity and stability of an immobilized biocatalyst can be influenced by the density of active sites [6], the occlusion of active sites in the complex [7], the prohibition of conformational changes of biocatalysts [8], restrictions of the spatial rotation of substrates [9], partitioning effects, and mass transfer limitations [6,10].…”

Analysis of substrate protection of an immobilized glucose isomerase reactor

“…',' The numerical scheme used for the differential bed reactor can also be applied to the packed bed reactor. The system of equations, (13)-(15), (17), and (19), can be solved by expressing the substrate concentration, C', which may again be expressed in the form of the Lagrange interpolation polynomial.…”

“…g a t ) amount of the immobilized enzyme (kg) Eq. (23) (dimensionless) density of enzyme in the immobilized beads (g/L) protection factor (dimensionless) voidage of the bed (dimensionless) porosity of particle (dimensionless) activity coefficient (dimensionless) Thiele modulus (dimensionless) overall effectiveness factor (dimensionless) process time (dimensionless) total operation time (h) space time (h) constant defined in Eq (19). film thickness of external mass transfer (cm) dimensionless Z (dimensionless)…”