Estimation of the intrinsic kinetic constants in the immobilized enzyme system

Abstract

Abstract The effect of mass transfer resistance on the reaction kinetics of immobilized glucose isomerase was studied, using a commercially available enzyme Swetase (Nagase Co., Japan). The effective diffusivity of glucose in the support matrix of Swetase was first determined experimentally with the Horowitz method. Using the concept of effectiveness factor encountered in reaction kinetics, a method for estimating the intrinsic kinetic parameters for immobilized glucose isomerase from reaction rates of the enzyme system was proposed. Knowing these intrinsic kinetic parameters along with the diffusivity of glucose within the enzyme particle, we can simulate Swetase's behavior in a CSTR, with a mathematical model. The simulated results compared very well with experimental values, indicating that the methods for determining enzyme kinetic parameters and substate diffusivity within the enzyme system were quite reliable.