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Techniques for the Evolution of Robust Pentose-fermenting Yeast for Bioconversion of Lignocellulose to Ethanol
Published on: October 24, 2016
Ethanol from whey: Continuous fermentation with cell recycle
J H Janssens1, A Bernard, R B Bailey
1Biotechnology Branch, Solar Energy Research Institute, Golden, Colorado 80401.
Biotechnology and Bioengineering
|January 1, 1984
Summary
This study optimized continuous fermentation of cheese whey lactose into ethanol using Kluyveromyces fragilis. The two-step process achieved high ethanol productivity without residual sugar, but productivity decreased at high sugar concentrations.
Area of Science:
- Biotechnology
- Industrial Microbiology
- Fermentation Technology
Background:
- Cheese whey is a rich source of lactose, a fermentable sugar.
- Efficient conversion of cheese whey into value-added products like ethanol is desirable.
Purpose of the Study:
- To optimize ethanol production from cheese whey lactose using continuous fermentation.
- To evaluate the performance of Kluyveromyces fragilis in a two-step continuous culture system with cell recycle.
Main Methods:
- A two-step continuous fermentation process was developed: aerobic fed-batch for biomass buildup, followed by anaerobic fermentation for ethanol production.
- A selected strain of Kluyveromyces fragilis was used.
- 100% cell recycle was implemented in the continuous culture.
Main Results:
- The optimized process achieved a maximum ethanol productivity of 7.1 g/L/h at a dilution rate of 0.15 h(-1).
- Zero residual sugar concentration was achieved, indicating complete lactose utilization.
- Ethanol productivity decreased when the feed sugar concentration exceeded 120 g/L, even with lipid supplementation.
Conclusions:
- Continuous fermentation with cell recycle is an effective strategy for ethanol production from cheese whey lactose.
- Kluyveromyces fragilis is a suitable microorganism for this bioprocess.
- High substrate concentrations pose a challenge for maintaining optimal productivity.
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