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Updated: Apr 28, 2026
14:53
Techniques for the Evolution of Robust Pentose-fermenting Yeast for Bioconversion of Lignocellulose to Ethanol
Published on: October 24, 2016
11.0K
[Process development for continuous ethanol fermentation by the flocculating yeast under stillage backset
Summary
To improve ethanol fermentation, avoid high temperatures and control stillage backset duration and pH. These strategies reduce propionic acid inhibition, boosting yeast biomass and ethanol yield.
Area of Science:
- Biotechnology
- Fermentation Science
- Yeast Physiology
Background:
- Propionic acid accumulation inhibits yeast during continuous ethanol fermentation.
- Stillage backset conditions in corn meal hydrolysate fermentation exacerbate this inhibition.
- Understanding propionic acid's mechanism is key to improving fermentation efficiency.
Purpose of the Study:
- To develop strategies for alleviating propionic acid inhibition in yeast.
- To optimize continuous ethanol fermentation using flocculating yeast.
- To enhance biomass and ethanol yields under stillage backset conditions.
Main Methods:
- Investigated the impact of medium sterilization temperature on propionic acid production.
- Controlled the duration of stillage backset to manage propionic acid levels below IC50.
- Adjusted fermentation pH to mitigate propionic acid's inhibitory effects.
Main Results:
- Avoiding medium sterilization significantly reduced propionic acid.
- Fermentation without sterilization increased biomass by 59.3% and ethanol by 7.4%.
- A higher pH of 5.5 proved optimal for fermentation under stillage backset.
Conclusions:
- High-temperature processes increase propionic acid; avoid them for better yields.
- Controlling stillage backset time and maintaining a pH of 5.5 are crucial for efficient fermentation.
- These strategies effectively alleviate propionic acid inhibition, enhancing ethanol production.
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