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Updated: Jul 4, 2026
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Operation of a Benchtop Bioreactor
Published on: September 12, 2013
Calorimetric control of fed-batch fermentations
T W Randolph1, I W Marison, D E Martens
1Institute of Chemical Engineering, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland.
Biotechnology and Bioengineering
|October 5, 1990
Summary
Controlled fermentation using Saccharomyces cerevisiae (yeast) heat production and carbon dioxide output led to high biomass yields and low ethanol levels. This method proved effective for optimizing yeast fermentation processes.
Area of Science:
- Biotechnology and Biochemical Engineering
- Microbial Fermentation Process Control
Background:
- Fed-batch fermentation is a critical process for producing biomass and metabolites using microorganisms like Saccharomyces cerevisiae.
- Effective control strategies are essential for maximizing product yield and minimizing byproducts, such as ethanol.
- Monitoring heat production offers a potential real-time indicator of metabolic activity during fermentation.
Purpose of the Study:
- To investigate the use of heat production measurements for controlling fed-batch fermentations of Saccharomyces cerevisiae.
- To evaluate the efficacy of a control strategy based on the ratio of carbon dioxide evolution rate to heat production.
- To assess the accuracy of biomass production estimation using heat measurements, particularly in nitrogen-limited conditions.
Main Methods:
- Utilized measurements of heat produced by Saccharomyces cerevisiae CBS 426.
- Implemented elemental and enthalpic balances for process control.
- Employed a proportional control system based on the ratio of carbon dioxide evolution rate to heat production.
- Varied controller gain relative to the maximum specific cellular growth rate.
Main Results:
- The proportional control strategy resulted in high biomass yields and minimized ethanol production.
- Biomass production estimations derived from heat measurements showed good agreement with actual measured values, especially in nitrogen-free carbon sources.
- Stable control was maintained even with significant fluctuations in feed concentrations when controller gain was below the maximum specific cellular growth rate.
Conclusions:
- Heat production measurement is a viable and effective parameter for controlling fed-batch fermentations of Saccharomyces cerevisiae.
- The ratio of carbon dioxide evolution rate to heat production provides a robust control mechanism for optimizing biomass yield and reducing ethanol byproduct.
- The developed control strategy ensures stable fermentation performance and accurate biomass estimation under various conditions.
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