Characterization and identification of saccharomyces uvarum from Okanagan white wine grapes and from their spontaneous fermentations

商业葡萄酒通常通过接种发酵生产，其中将酿酒酵母的单一商业菌株添加到发酵中，或者通过自发发酵生产，其依赖于来自葡萄园和酿酒厂环境的常驻葡萄酒酵母。自发发酵的特征是酵母属、种和菌株的多样性演替，其中具有一个或多个更耐乙醇的S.酿酒酵母通常占主导地位的中期和最后阶段。酿酒厂使用自发发酵的一个动机是生产具有更复杂感官特征的葡萄酒，这可能是由于产生了来自不同酵母菌群的多种代谢副产物。自然发酵可以使用，因为它们可以在葡萄酒中产生区域特征（风土），这是由于区域特定酵母的存在。我们在霞多丽和灰比诺葡萄的自发发酵中鉴定出葡萄汁酵母，一种耐低温、高甘油和低乙酸的酵母。我们的目标是确定：1）是否S。uvarum能够在多年的发酵中占主导地位; uvarum是否起源于酿酒厂或葡萄园;不同纬度的Okanagan葡萄园在葡萄上和发酵过程中的葡萄汁囊菌菌株存在差异;葡萄囊，可以潜在地提高发酵性能和感官档案的奥卡诺根白色葡萄酒。为了解决第一个和第二个目标，我们将收集霞多丽葡萄从一个葡萄园和比较的S。葡萄、葡萄酒表面和实验室发酵之间的葡萄皮种群。为了解决第三个目标的区域特定的S。uvarum酵母，我们将比较S.葡萄皮在不同纬度的葡萄园之间生长。我们将使用Illumina DNA测序来鉴定酵母菌种，并使用微卫星分型来表征S。来自目标1、2和3的葡萄和葡萄酒样品的葡萄囊菌菌株。对于第四个目标，S.将对葡萄汁囊分离物进行筛选，以确定实验室发酵过程中产生的特定化学物质。

Commercial wines are typically produced either by inoculated fermentation, in which a single commercial strain of Saccharomyces cerevisiae is added to the fermentation, or by spontaneous fermentation, which relies on resident wine yeasts from the vineyard and winery environments. Spontaneous fermentation is characterized by a diverse succession of yeast genera, species, and strains, with either one or multiple strains of the more ethanol-tolerant S. cerevisiae usually dominating the mid and final stages. One motivation for a winery to use spontaneous fermentations is to produce wine with a more complex sensory profile, which islikely due to the production of a diversity of metabolic by-products derived from a diverse yeast community. Spontaneous fermentations may be used because they can produce a regional character (terroir) in the wine due to the presence of region-specific yeast. We have identified Saccharomyces uvarum, a cryotolerant, high glycerol and low acetic acid-producing yeast, in spontaneous fermentations of Chardonnay and Pinot Gris grapes. Our objectives are to determine: 1) whether S. uvarum is able to dominate fermentations in multiple years; 2) whether S. uvarum is originating from the winery or vineyard; 3) whether S. uvarum strains on grapes and in fermentations differ between Okanagan vineyards at different latitude; and 4) whether there is aregionally distinct population of S. uvarum that could potentially enhance the fermentation properties and sensory profiles of Okanagan white wines. To address the first and second objectives, we will collect Chardonnay grapes from one vineyard and compare the S. uvarum populations between grapes, wine surfaces and in-lab fermentations. To address the third objective of region specific S. uvarum yeasts, we will compare the relative abundance of S. uvarum strains between vineyards at different latitudes. We will use Illumina DNA sequencing to identify yeast species and microsatellite typing to characterize S. uvarum strains from grape and wine samples from objectives 1, 2 and 3,. For the fourth objective, S. uvarum isolates will be screened forspecific chemicals produced during in-lab fermentations.