Yeast that gave birth to lager beer discovered in Patagonia

Washington, August 23 (ANI): After decades of searching, scientists have finally discovered the origins of the yeast that made lager beer possible.

It apparently comes from the beech forests of Patagonia, the alpine region at the tip of South America.

"People have been hunting for this thing for decades," explains Chris Todd Hittinger, a University of Wisconsin-Madison genetics professor and a co-author of the new study.

"And now we've found it. It is clearly the missing species. The only thing we can't say is if it also exists elsewhere (in the wild) and hasn't been found."

Until now, scientists were puzzled as to why they could not find the origins of lager yeast among the 1,000 known species in the world. The unique yeast allows lager to brew at cold temperatures.

The newfound yeast, dubbed Saccharomyces eubayanuse was discovered as part of an exhaustive global search, led by the New University of Lisbon's Jose Paulo Sampaio and Paula Goncalves.

Team member Diego Libkind of the Institute for Biodiversity and Environment Research in Bariloche, Argentina, found S. eubayanus in galls on southern beech trees in Patagonia. The galls were particularly rich in sugar, which yeast like to colonize and consume.

The yeast is so active in the galls, according to Libkind, that they spontaneously ferment.

When the team brought the yeast to a lab at the University of Colorado and analyzed its genome, they discovered that it was 99.5 percent identical to the non-ale portion of the S. pastorianus genome, suggesting it was indeed lager yeast's long-lost ancestor.

Researchers believe the forest yeast made its way to Bavaria's brewing caves as a stowaway perhaps in a piece of wood or in the belly of a fruit fly.

The study was recently published in the Proceedings of the National Academy of Sciences. (ANI)