Modeling methods used to optimize the biocatalytic efficiency of freely suspended cells have been applied to non-growing microbial cells entrapped within a macro-porous carrier. The catalytic rate, which is dependent on cell concentration inside the biocatalyst beads, coincided with catalytic parameters for freely suspended cells. Immobilized non-growing cell systems could be optimized utilizing the characteristics of freely suspended cells without requiring extensive experimentation to define catalytic behaviour inside the biocatalyst. A dynamic diffusion-reaction model was developed and validated using experimental data for thiodiglycol degradation by Alcaligenes xylosoxidans subsp. xylosoxidans immobilized within macro-porous poly(vinyl alcohol) cryogel in a completely mixed batch bioreactor.