Nitrogen is a critical nutrient in beverage fermentations, influencing fermentation performance and formation of compounds that affect organoleptic properties of the product. Traditionally, most commercial wine fermentations rely on Saccharomyces cerevisiae but the potential of alternative yeasts is increasingly recognised because of the possibility to deliver innovative products and process improvements. In this regard, Saccharomyces uvarum is an attractive non-traditional yeast that, while quite closely related to S. cerevisiae, displays a different fermentative and aromatic profile. Although S. uvarum is used in cider-making and in some winemaking, better knowledge of its physiology and metabolism is required if its full potential is to be realised. To address this gap, we performed a comparative analysis of the response of S. uvarum and S. cerevisiae to 13 different sources of nitrogen, assessing key parameters such as growth, fermentation performance, the production of central carbon metabolites and aroma volatile compounds. We observed that the two species differ in the production of acetate, succinate, medium-chain fatty acids, phenylethanol, phenylethyl acetate and fusel/branched acids in ways that reflect different distribution of fluxes in the metabolic network. The integrated analysis revealed different patterns of yeast performance and activity linked to whether growth was on amino acids metabolised via the Ehrlich pathway or on amino acids and compounds assimilated through the central nitrogen core. This study highlights differences between the two yeasts and the importance that nitrogen metabolism can play in modulating the sensory profile of wine when using S. uvarum as the fermentative yeast.

中文翻译：

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葡萄酒发酵中葡萄酵母的生长和代谢组受到氮同化途径的强烈影响

氮是饮料发酵中的关键营养素，影响发酵性能和影响产品感官特性的化合物的形成。传统上，大多数商业葡萄酒发酵依赖于酿酒酵母，但由于有可能提供创新产品和工艺改进，替代酵母的潜力越来越受到认可。在这方面，Saccharomyces uvarum 是一种有吸引力的非传统酵母，虽然与酿酒酵母密切相关，但显示出不同的发酵和芳香特性。虽然 S. uvarum 用于苹果酒酿造和一些酿酒，但如果要充分发挥其潜力，就需要对其生理学和新陈代谢有更好的了解。为了解决这一差距，我们对 S. uvarum 和 S. 的反应进行了比较分析。酿酒酵母对 13 种不同的氮来源，评估关键参数，如生长、发酵性能、中心碳代谢物的产生和香气挥发性化合物。我们观察到这两个物种在乙酸盐、琥珀酸盐、中链脂肪酸、苯乙醇、乙酸苯乙酯和杂醇/支链酸的生产方面存在差异，反映了代谢网络中通量的不同分布。综合分析揭示了酵母性能和活性的不同模式与生长是依赖于通过埃利希途径代谢的氨基酸还是依赖于通过中央氮核同化的氨基酸和化合物有关。这项研究强调了两种酵母之间的差异以及氮代谢在使用 S 时调节葡萄酒感官特征的重要性。