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

商业葡萄酒通常是通过接种发酵生产的，在发酵过程中加入单一的商业酿酒酵母菌株，或者通过自然发酵生产，自然发酵依赖于葡萄园和葡萄酒厂环境中的驻留葡萄酒酵母。自然发酵的特征是酵母属、种和菌株的多样性演替，一个或多个更耐酒精的酿酒酵母菌株通常在中后期占据主导地位。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，这可能是因为从不同的酵母群落产生了不同的代谢副产品。可以使用自发发酵，因为它们可以在葡萄酒中产生区域特征(由于存在特定区域的酵母菌)。我们在夏敦埃葡萄和灰皮诺葡萄的自然发酵中鉴定出一种耐冷性、高甘油和低醋酸的酵母-uvarum。我们的目标是确定：1)Uvarum是否能够在多年中主导发酵；2)S.uvarum是否来自酒庄或葡萄园；3)葡萄和发酵中的S.uvarum菌株是否在不同纬度的Okanagan葡萄园之间有所不同；以及4)是否存在**地区不同的S.uvarum种群，从而潜在地提高Okanagan白葡萄酒的发酵特性和感官特征。为了解决第一个和第二个目标，我们将从一个葡萄园采集霞多丽葡萄，并比较葡萄、葡萄酒表面和实验室发酵之间的S.uvarum种群。为了解决第三个目标的地区特定的葡萄球菌uvarum酵母，我们将比较葡萄园在不同纬度的相对丰富的uvarum菌株。我们将使用Illumina DNA测序来鉴定酵母种类，并使用微卫星分型来鉴定目标1、2和3中的葡萄和葡萄酒样品中的葡萄球菌菌株。对于第四个目标，将对uvarum分离株进行筛选，以寻找在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 is**likely 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 a**regionally 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 for**specific chemicals produced during in-lab fermentations.