UBC Theses and Dissertations

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UBC Theses and Dissertations

The diversity and function of Indigenous yeasts in the Okanagan Region of British Columbia. Lyons, Sarah Marie A


Consumer preference in the wine industry is encouraging wine makers to produce more unique wines than ever before. One way in which to add such distinctiveness to a wine is to utilize the microbial diversity present in each region. This can be done by spontaneous fermentations; however, this carries risks of spoilage or stuck fermentations and lacks the consistency of inoculated fermentations. More research is needed to understand the diversity of yeasts in vineyards and how some indigenous strains could be utilized by wineries in a more controlled fashion. My thesis aims to better characterize the microbial diversity in vineyards and how they respond to environmental perturbations as well as to characterize the fermentative properties of unique strains isolated from fermentations in the Okanagan region. To accomplish this, I first investigated the fungal communities on grapes in 3 vineyards in the Okanagan region after environmental disturbances. Experimental vines were exposed to either simulated forest fire smoke, one of three agricultural sprays, or both smoke and sprays. Amplicon based Next Generation Sequencing was then used to profile the fungal communities on the grapes before exposure, two weeks after exposure, and again at harvest. We revealed that fungal communities are robust to these disturbances and no differences were found after exposure between the experimental vines and the control vines. In the second research chapter of my thesis, I performed controlled fermentations of chardonnay juice using unique strains isolated from wineries in the Okanagan region. These strains were found to be abnormally competitive in previously conducted winery fermentations, some even out-competing commercially sourced yeast strains. Others were found in relatively high abundance in wineries for multiple years in a row. By analyzing the fermentation kinetics and the production of volatile compounds using GC-MS, we found that many of these strains had comparable fermentation kinetics to commercial strains at both 12 °C and 15 C, and produced unique compound profiles that could be used by local wineries to produce more complex and regionally specific wines.

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