Immobilized cell biocatalyst activation and pseudo-steady-state behavior: model and experiment.

An intrinsic, unstructured model has been utilized to describethe startup dynamics of a continuous Caalginate-immobilized Zymomonas mobilis (ATCC 10988) fermentation. This model predicts, at least qualitatively, transients in the fermenter effluent glucose, ethanol, and biomass concentrations as well as radial gradients in immobilized-cell concentration and activity within the gelbiocatalysts. Predicted intrabiocatalyst gradients in immobilized-cell specific growth rate were used to calculate the corresponding gradients in intracellular RNA level based on a reported linear relationship between the two. Mathematical simulations of immobilized biomass concentration profiles and RNA content were verified using a novel, scanning microfluorimetry technique.