The role of acetaldehyde and glycerol in the adaptation to ethanol stress of Saccharomyces cerevisiae and other yeasts |
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| Authors: | Frank Vriesekoop Cornelia Haass & Neville B Pamment |
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| Institution: | Institute for Food and Crop Science, School of Science and Engineering, University of Ballarat, Ballarat, Vic., Australia;and;Department of Chemical and Biomolecular Engineering, The University of Melbourne, Vic., Australia |
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| Abstract: | Ethanol inhibition is a commonly encountered stress condition during typical yeast fermentations and often results in reduced fermentation rates and production yields. While past studies have shown that acetaldehyde addition has a significant ameliorating effect on the growth of ethanol-stressed Saccharomyces cerevisiae , this study investigated the potential ameliorating effect of acetaldehyde on a wide range of ethanol-stressed yeasts. Acetaldehyde does not appear to be a universal ameliorating agent for yeasts exposed to ethanol stress. It is also shown that as a result of an ethanol stress, most yeasts rapidly produce glycerol as an alternative means of NAD+ regeneration rather than having a specific requirement for glycerol. The results strongly suggest that both ethanol and acetaldehyde exposure have a direct effect on the cellular NAD+/NADH ratio, which can manifest itself as modulations in glycerol production. |
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| Keywords: | acetaldehyde glycerol redox yeast ethanol stress |
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