Grant: Discovery Grants Program - Individual

Our research program uses the natural diversity of yeast to benefit the fermented beverage biotechnology industry, in particular the Canadian wine industry. Wine is the product of alcoholic fermentation of grape juice typically by the yeast Saccharomyces cerevisiae (S. cerevisiae). The majority of flavour and aroma compounds in wine are produced during alcoholic fermentation by S. cerevisiae. Wine was fermented by ancient civilizations for thousands of years using the natural microflora on the grapes and wine equipment. The natural habitats of yeasts include soil, fruits and trees. The yeast scientific research community has collected S. cerevisiae strains from all over the world in both natural and industrial environments. Using whole genome sequencing technologies to understand the genealogy of S. cerevisiae, it has been shown that commercial wine yeast strains evolved from strains isolated from Mediterranean Oak trees, which is perhaps unsurprising given that wine grapes originated from this region. Commercial wine yeast strains, which have been isolated from European wine regions, are genetically very similar (inbred) and therefore are limited in the complexity of the wine metabolites they can produce. Compared to Europe and other wine producing regions, the biodiversity of North American wine yeast strains is relatively unexplored. Using natural wine fermentations, we have collected hundreds of new strains of S. cerevisiae isolated from the Okanagan Valley, the major wine region in British Columbia (BC). Interestingly, we have identified a new S. cerevisiae population in BC wine fermentations that is not genetically related to European commercial strains. We have named this new S. cerevisiae population the Pacific West Coast Wine (PWCW) family and we have found that it extends into the Napa Valley wine region of California. Our proposed research program aims to explore and expand the biodiversity of Pacific West Coast wine yeast strains by collecting yeast from other Canadian wine regions such as Vancouver Island and the Niagara peninsula. Canadian wineries have a commercial interest in using S. cerevisiae strains isolated from their vineyards as wine fermentation starter cultures. We will screen our large collection of yeast for fitness in response to stresses encountered during wine fermentation, such as the sulfites that are added to grape juice to prevent microbial spoilage and oxidation of wine. We will also uncover the genetic traits important for generating flavour and aroma metabolites during wine making. This data will help the fermentation industry screen and select strains for beverage production. Our biodiverse yeast collection will be used to enrich the fundamental academic understanding of the S. cerevisiae cellular pathways that are responsible for stress resistance as most of the knowledge has been gleaned from a single laboratory strain. Our program will train highly qualified personnel for the Canadian workforce.