Identification and characterization of indigenous B.C. wine yeast strains

在竞争激烈的葡萄酒市场中，不列颠哥伦比亚省（BC）的酿酒厂必须创造高价值的葡萄酒，以表达其地区的独特个性或风土。葡萄酒是通过接种葡萄酒酵母酿酒酵母（S。酿酒厂）或通过自然发酵，这依赖于酵母驻留在葡萄和酿酒设备。自发发酵是有风险的，但如果本土酵母菌占主导地位，可以产生感官复杂的葡萄酒。 我的研究目标是识别BC省葡萄园中存在的土著酵母，这些酵母具有展示BC省风土的酿酒潜力。自2013年以来，我们与BC省的两家酒庄合作，进行灰比诺和黑比诺的自然发酵。在酒厂发酵的同时，我们收获了相同的葡萄品种，并在实验室中发酵。分离出S.酿酒厂和葡萄园发酵的酿酒酵母菌株，进行微卫星分析，并将数据与我们汇编的120多个商业S.酿酒葡萄酒酵母菌株。我们已经确定了一个独特的土著亚群的S。酿酒酵母和意外鉴定的S. bayanus在发酵。 我们的小说S。cerevisiae和S. bayanus菌株具有酿酒潜力。目的1. 表型和代谢谱的S。从自发发酵中分离的酿酒酵母菌株。贝叶斯聚类分析，我们的S。酿酒酵母菌株显示12个群体聚类。我们将使用每个集群的代表性菌株进行小规模发酵。将分析具有剧烈发酵特征的菌株的阳性风味化合物。将对葡萄酒生产的重要性状进行表型分析，并对具有酿酒潜力的菌株进行全基因组测序。*目标2. 自发发酵过程中酵母菌/真菌菌种的鉴定。非传统的酵母，如Metschnikowia，在自发发酵中发现，并为葡萄酒提供感官复杂性。我们将通过从葡萄酒样品中直接提取DNA和Illumina下一代测序来识别我们的酿酒厂和葡萄园发酵中存在的非酵母菌属物种。我们的目标是分析非传统酵母对酿酒厂和葡萄园发酵的贡献。 * 目标3。BC S的遗传特性。bayanus分离物和评价。bayanus和非酵母菌发酵潜力。我们分离了独特的S. bayanus来自灰皮诺的自发发酵。 我们将生成一个S。bayanus参考数据库使用商业和公开的菌株对亚群进行分类。 S. bayanus和非酵母菌株将与S.酿酒酵母菌株，以确定高品质葡萄酒生产的理想菌株组合。 **

In competitive wine markets, British Columbian (BC) wineries must create high-value wines that express the unique character, or terroir, of their region. Wines are produced by inoculated fermentation with commercial strains of the wine yeast Saccharomyces cerevisiae (S. cerevisiae) or by spontaneous fermentation, which relies on yeast residing on grapes and winery equipment. Spontaneous fermentations are risky but can produce organoleptically complex wines if indigenous yeast species dominate the fermentation. The goal of my research is to identify indigenous yeast present in BC vineyards with enological potential that showcase BC terroir. Since 2013, we have collaborated with two BC wineries that perform Pinot Gris and Pinot Noir spontaneous fermentations. Concurrent with winery fermentations, we harvested the same grape varietals and fermented them in the lab. We isolated S. cerevisiae strains from winery and vineyard fermentations, performed microsatellite profiling and compared the data to a microsatellite database that we compiled of over 120 commercial S. cerevisiae wine yeast strains. We have identified a unique indigenous subpopulation of S. cerevisiae and unexpectedly identified strains of S. bayanus in the fermentations. Both our novel S. cerevisiae and S. bayanus strains have enological potential.***Objective 1. Phenotypic and Metabolic profiling of S. cerevisiae strains isolated from spontaneous fermentations. Bayesian clustering analysis of our S. cerevisiae strains revealed 12 population clusters. We will perform small-scale fermentations with representative strains from each cluster. Strains with vigorous fermentation profiles will be analyzed for positive flavor compounds. Phenotypic analysis of traits important for wine production and whole genome sequencing of strains with enological potential will be performed.***Objective 2. Identification of yeast/fungal species during spontaneous fermentation. Nonconventional yeasts such as Metschnikowia are found in spontaneous fermentations and contribute sensorial complexity to the wine. We will identify non-Saccharomyces species present in our winery and vineyard fermentations by direct DNA extraction from wine samples and Illumina next generation sequencing. Our goal is to analyze the contribution of nonconventional yeast to the winery and vineyard fermentations. ***Objective 3. Genetic characterization of BC S. bayanus isolates and evaluation of S. bayanus and non-Saccharomyces yeast fermentation potential. We isolated unique strains of S. bayanus from Pinot Gris spontaneous fermentations. We will generate an S. bayanus reference database using commercial and published strains to classify subpopulations. S. bayanus and non-Saccharomyces strains will be co-inoculated with S. cerevisiae strains to identify ideal strain combinations for high quality wine production. **