Development and verification of a model to describe an immobilized glucose isomerase packed bed bioreactor

In this paper, the performance of immobilized packed bed glucose isomerase enzyme was mathematically modeled. A modified Michaelis-Menten type relation was used to describe the enzyme kinetics. Mass transfer inside the biocatalyst particle and through the bed column was analyzed simultaneously. Using measured data, physicochemical properties including diffusivity, viscosity and density of sugar solutions were correlated with its concentrations and were used to provide precision in solving the set of model equations. Model equations were solved using the Runge-Kutta and Gauss-Seidel algorithms and finite difference numerical method in MATLAB environment. Model output was used to demonstrate the effect of parameters such as velocity and bulk substrate concentration on the concentration profile within the biocatalyst particle, effectiveness factor and bulk substrate concentration along the bed. Model predictions were further validated against experimental data collected from a lab scale isomerization bioreactor. Measurements of the overall bioreactor conversion at various substrate concentrations were shown to lie within 5% of the values as put forth by the model. Using experimental data, a criteria was proposed to maximize the isomerization conversion from the immobilized bioreactor.