Independent Validation of Differing Nitrogen Requirements Among Wine Yeast Strains
| dc.contributor.author | Wayne, Ian | |
| dc.date.accessioned | 2023-07-03T14:47:05Z | |
| dc.date.available | 2023-07-03T14:47:05Z | |
| dc.date.issued | 2023 | |
| dc.description.abstract | Nitrogen is an essential nutrient for all life. For the budding yeast Saccharomyces cerevisiae, nitrogen is required for amino acid, nucleotide, and biomass synthesis, which in turn influence metabolic processes in the cell. Winemakers consistently cite nitrogen limitation as a leading cause of both “stuck or sluggish” fermentations – in which yeast do not reach “dryness,” meaning they fail to convert glucose and fructose to ethanol – and the accumulation of undesirable flavor and aroma compounds such as hydrogen sulfide (H₂S). Commercial yeast suppliers include nitrogen requirements among a longer list of characteristics which winemakers may use to ensure a chosen yeast is supplied with appropriate nutrition. While crucial details about nitrogen metabolism in both laboratory and winemaking yeast strains are known – including the genes responsible for the sensing and signaling of environmental nitrogen sources, and the cell’s response to nitrogen limitation under various conditions of stress – open questions about strain-specific requirements for nitrogen remain. Studies that show variation in nitrogen utilization do so using a steady-state growth apparatus to measure nitrogen consumed during stationary phase, once cells have reached maximum density and are no longer forming biomass. Other studies suggest that nitrogen availability during the exponential growth phase constitutes the most important period for wine yeast. Furthermore, the combination of stressors that are typical of wine fermentations – high levels of ethanol, low pH, and low nutrient availability – make it difficult to isolate the impact of a single condition. This work aims to independently validate existing knowledge about yeast strain-specific nitrogen utilization by comparing the fermentation kinetics, cell density, and sugar and nitrogen metabolism of 6 commercial wine strains under typical winemaking conditions. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1813/113318 | |
| dc.rights | Attribution 4.0 International | * |
| dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | * |
| dc.title | Independent Validation of Differing Nitrogen Requirements Among Wine Yeast Strains | en_US |
| dc.type | dissertation or thesis | en_US |
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