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A study of ethanol tolerance in yeast
T D'Amore1, C J Panchal, I Russell
1Research Department, Labatt Brewing Company Ltd., London, Ontario, Canada.
Critical Reviews in Biotechnology
|January 1, 1990
Summary
Yeast ethanol tolerance is complex, influenced by factors like media composition and temperature. Nutrient limitation, not just intracellular ethanol, impacts yeast growth and fermentation at high osmotic pressure.
Area of Science:
- Microbiology
- Biotechnology
- Biochemistry
Background:
- Ethanol tolerance in yeast is a long-standing, controversial topic due to complex inhibition mechanisms and undefined measurement methods.
- Factors influencing ethanol tolerance include plasma membrane composition, media, substrate feeding, osmotic pressure, temperature, and byproduct formation.
Purpose of the Study:
- To investigate the multifaceted factors affecting yeast ethanol tolerance.
- To clarify the roles of intracellular ethanol accumulation and nutrient limitation in yeast fermentation performance.
Main Methods:
- Analysis of yeast fermentation under varying conditions (media composition, osmotic pressure, temperature).
- Monitoring of intracellular and extracellular ethanol concentrations during fermentation.
- Assessment of yeast growth and fermentation activity in response to environmental factors.
Main Results:
- Media composition significantly impacts yeast's ability to ferment concentrated substrates and at higher temperatures.
- Supplementation with peptone-yeast extract, magnesium, or potassium salts enhances fermentation rates.
- Nutrient limitation, rather than solely intracellular ethanol accumulation, contributes to reduced yeast activity at high osmotic pressure and temperature.
Conclusions:
- Yeast ethanol tolerance is a complex phenotype influenced by multiple environmental and cellular factors.
- Optimizing media composition and understanding nutrient limitation are crucial for improving yeast fermentation efficiency in challenging conditions.