Bisson Lab in the news for non-GMO sulfurless yeast
Dr. Bisson using that expert nose
A winemaking yeast strain invented by a UC Davis researcher that removes the sulfur odor in wines has been patented and is undergoing development and marketing around the world and locally.
The non-genetically modified yeast was developed by Linda Bisson of the UCD department of viticulture and enology and is being marketed in partnership with Vancouver-based Renaissance BioScience Corp.
Local winemakers have heard of the new yeast and could be using the strain to make wine as early as this summer’s harvest, and some larger winemakers already have begun to use the new yeast in blends.
The yeast strain, used in fermentation to make wine, was bred through traditional methods to select for a new yeast that produces less hydrogen sulfide, which has an undesirable rotten egg smell, Bisson said. Even at low levels, hydrogen sulfide can mute the desired fruit characteristics of wines.
Taken under 100x phase contrast
From UC Davis Viticulture and Enology Wine Yeast and Bacteria Collection: http://wineserver.ucdavis.edu/content.php?category=Research&id=367
For more photos see http://enologyaccess.org/
Taken under 100x DIC (Differential Interference Contrast)
From the Wine Yeast and Bacteria Collection: http://wineserver.ucdavis.edu/content.php?category=Research&id=367
See more photos at http://enologyaccess.org/
Saccharomyces cerevisiae in media
Taken under 100 x (oil) objective during log phase growth. Courtesy of the UC Davis Wine Yeast and Bacteria collection
To see more photos go to http://enologyaccess.org/
From Discover Magazine By Veronique Greenwood
Yeasts are handy little critters: they help produce the alcohol that make wine and beer so deliciously intoxicating. But how they manage to show up on grapes in vineyards year after year, despite freezing winters when there is little for them to eat, is a bit of a mystery. Scientists thought birds could be keeping the yeasts in their guts through the winter, then sprinkling them (ahem) through vineyards in the spring, but turned out the microorganisms couldn’t survive that long in birds.
Now, scientists have identified a much more promising Florida timeshare of a gut: that of the social wasp. Social wasps feed on vineyard grapes, and their queens do survive the winter, emerging from hibernation to found new colonies in the spring. Italian researchers checked the gut microbes of 61 social wasps collected in Tuscany and other wine regions and found that there were scads of yeasts there, 393 strains to be exact. The wasps carried some yeasts that are similar to those found in the area’s wines, suggesting that they may indeed be a significant year-round reservoir of the microorganisms.
Italian wine owes some of its character to local yeasts, scientists have reported before, and this study lends credence to the idea that it’s not possible to separate conservation of local ecosystems and artisanal food production.
While this is certainly an intriguing idea, Saccharomyces cerevisiae can be pretty hardy little buggers on their own without needed to take shelter in the guts of insects. When presented with less than optimal growth conditions yeasts can revert into a semi quiescent survival mode where they build up stores of glycogen and trehalose to strengthen their membranes. Or given really unfavorable conditions yeasts can sporulate and create spores that can easily tolerate a wide range of environmental stresses.