(December 5, 2015) About
500 years ago, the accidental natural hybridization of Saccharomyces
cerevisiae, the yeast responsible for things like ale, wine and bread, and a
distant yeast cousin gave rise to lager beer.
Today, cold-brewed lager is the world's most consumed
alcoholic beverage, fueling an industry with annual sales of more than $250
billion.
The first lagers depended on the serendipitous cross of
Saccharomyces species as evolutionarily diverse as humans and chickens. The
result, however, yielded a product of enormous economic value, demonstrating
the latent potential of interspecies yeast hybrids. In nature, the odds of a
similar hybridization event are, conservatively, one in a billion.
Now, thanks to a new method for making interspecies yeast
hybrids in the lab, the makers of beer, wine, biofuels and other products that
depend on yeasts may soon have many more strains of the microorganism to work
with.
"We can achieve hybrids at rates of one in a thousand
cells," notes William Alexander, a University of Wisconsin-Madison
postdoctoral research associate and the lead author of a paper describing the
new method in a special synthetic biology issue of the journal Fungal Genetics
and Biology. "It is much more efficient than nature."
There are hundreds of known species of yeasts and they
occupy almost every ecological niche imaginable worldwide. They are essential
to the process of fermentation, where the microbes convert sugars to alcohol
and carbon dioxide. Yeasts are used widely to not only make beer, wine and
bread, but also cider, whiskey, cheese, yogurt, soy sauce and an array of other
fermented foods and beverages. In industry, yeasts are used to produce biofuels
and to make enzymes, flavors and pigments and even drugs such as human insulin.