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Updated: Jul 4, 2026
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Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability
Published on: April 22, 2016
Immobilized cell biocatalyst activation and pseudo-steady-state behavior: model and experiment
H G Monbouquette1, G D Sayles, D F Ollis
1Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA.
Biotechnology and Bioengineering
|March 15, 1990
Summary
A new model describes Zymomonas mobilis fermentation startup dynamics, predicting glucose, ethanol, and biomass changes. It also details cell concentration and activity gradients within the immobilized biocatalysts.
Area of Science:
- Biotechnology
- Biochemical Engineering
- Microbial Fermentation
Background:
- Continuous fermentation using immobilized Zymomonas mobilis (ATCC 10988) is crucial for ethanol production.
- Understanding the startup phase dynamics is essential for optimizing fermentation efficiency.
- Intracellular gradients within immobilized cells can significantly impact overall fermentation performance.
Purpose of the Study:
- To develop and utilize an intrinsic, unstructured model to describe the startup dynamics of continuous Ca-alginate-immobilized Zymomonas mobilis fermentation.
- To predict transient changes in key fermentation parameters and spatial gradients within the biocatalyst.
- To investigate the relationship between cell growth rate and intracellular RNA levels within the immobilized system.
Main Methods:
- Development of an intrinsic, unstructured mathematical model for fermentation startup.
- Simulation of effluent concentrations (glucose, ethanol, biomass) and radial gradients (cell concentration, activity).
- Calculation of intracellular RNA gradients based on predicted specific growth rate gradients and a known linear relationship.
Main Results:
- The model qualitatively predicts transients in glucose, ethanol, and biomass concentrations during fermentation startup.
- The model successfully predicts radial gradients in immobilized-cell concentration and activity within the Ca-alginate gel.
- Predicted intrabiocatalyst gradients in specific growth rate correlate with intracellular RNA levels.
Conclusions:
- The developed model provides valuable insights into the startup dynamics of immobilized Zymomonas mobilis fermentation.
- The study highlights the importance of considering spatial gradients within biocatalysts for accurate fermentation modeling.
- Mathematical simulations were validated using a novel scanning microfluorimetry technique, confirming predicted biomass concentration profiles and RNA content.
