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

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 degrees C and ph 6.0 was developed. Comparison of the model with actual experimental results were made showing average deviations of ca. 30-40%.