An assessment of ethanol stress stress tolerance factors in Saccharomyces cerevisiae

Ethanol, one of the main end products of sugar catabolism in yeast, can become a significant stress factor as it accumulates in the culture broth during fermentation. , Stressful ethanol levels can inhibit yeast growth rate, cell viability, metabolic activity, membrane-associated transport systems and, depending on the ethanol concentration, result in cell death. Ultimately, ethanol toxicity affects the fermentation performance of yeast resulting in lowered fermentation productivity and ethanol yield. To survive ,, and multiply under ethanol stress conditions, yeast cells have developed a set of sensing, signalling and defence mechanisms that enable them to rapidly acclimatise to ethanol toxicity. There is currently only limited knowledge of the complex mechanisms involved in the ethanol stress response of yeast; improving our understanding of these cellular , mechanisms could assist in the design of new yeast strains that are more ethanol tolerant and therefore less likely to be compromised during ethanologenic fermentation. It may also lead to the development of strategies and practices that better prepare yeast for fermentation-related stress and improve ethanol productivity and yield. This study was conducted to resolve some of the controversy associated with two ethanol stress tolerance factors in Saccharomyces cerevisiae, trehalose and the protein Asr 1