Mathematical modeling of ethanol production by immobilizedZymomonas mobilis in a packed bed fermenter

Abstract
A mathematical model which describes ethanol production in a packed bed fermenter containing. Zymomonas mobilis entrapped in small spheres of calcium alginate within a packed bed fermenter has been developed. The equations combine simultaneous diffusion and reaction as well as a complex flow pattern to calculate glucose and ethanol profiles in the column type reactor. As part of the study, diffusivity values for glucose and ethanol in cell‐loaded calcium alginate were determined. Also a freecell kinetic expression for Z. mobilis at 33°C and ph 6.0 was developed. Comparison of the model with actual experimental results were made showing average deviations of ca. 30–40%.