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Dr. David E. Block
Professor and Marvin Sands Department Chair and Holder of
Ernest Gallo Endowed Chair, Department of Viticulture & Enology
Professor, Department of Chemical Engineering and Materials Science
University of California, Davis
Website
Bio:
Professor Block is Marvin Sands Department Chair in Viticulture and Enology at UC Davis and holds the Ernest Gallo Endowed Chair in
Viticulture and Enology. Since joining UC Davis, he has conducted research on various topics, from fermentation optimization methods to metabolic engineering of yeast for improved wine production, and played a key role in designing the UC Davis LEED Platinum
certified Teaching and Research Winery. He has received the Distinguished Teaching Award from the UC Davis Academic Senate. Prior to joining UC Davis, he worked for Hoffmann-La Roche, Inc. working on biopharmaceutical process development and manufacturing.
David holds a B.S.E. from the University of Pennsylvania and a Ph.D. from the University of Minnesota, both in Chemical Engineering.
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“Elucidating the Mechanism of Ethanol Tolerance in
Saccharomyces cerevisiae”
Tuesday, September 12, 2017
3:00 p.m. – 4:15 p.m.
FRNY G140
– Reception at 2:30 p.m. in BASEMENT LOBBY –
Abstract:
The yeast
Saccharomyces cerevisiae is key to the production of ethanol through fermentation—whether for use as a biofuel or a beverage such as wine or beer.
S. cerevisiae has evolved to be highly ethanol tolerant, able to survive in concentrations as high as 20% vol/vol. However, cases where yeast lose their ethanol tolerance in commercial fermentations are a persistent problem, which can be either expensive
or impossible to rectify. Our work to understand and predict fermentation kinetics began with a classical modeling approach, which suggested that yeast cells were becoming inactivated prior to dying. We hypothesized that this inactivation was due to physical
changes in yeast cell lipid bilayer membrane in the presence of ethanol. Studies with purified lipid bilayers showed significant changes to membrane thickness and lipid spacing in the presence of ethanol that were highly dependent on membrane lipid composition.
To follow up on these results, we then studied 22 commercial yeast strains with a range of observed growth characteristics and ethanol tolerance. Using LC-MS, we were able to fully characterize the lipid composition of each of the strains. We found that
ethanol tolerance per cell is highly correlated with lipid composition, as hypothesized, and identified key lipids associated with the presence or absence of ethanol tolerance. Unexpectedly, we also observed that lipid composition is even more highly correlated
with nutrient utilization efficiency in yeast, which can also be related to observed ethanol tolerance. To understand this relationship, we have used a combination of lipidomic, metabolomic, and transcriptomic analyses.
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