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For the first time in Europe, scientists have discovered the ancestor of the yeast species needed to produce lager beer.
Brewing is one of the oldest human industries, and scientists have discovered evidence of fermented beverages at least 7,000 years ago in China and 13,000 years ago in Israel.
Modern brewing developed in Europe, where until the Middle Ages, most beer brewing involved a yeast called Saccharomyces cerevisiae.
Today this species of yeast is still used to make ale-style beer, wine and bread.
Our undergraduates have found hundreds of yeast species in Irish soil samples over the past five years, and we have S. Delighted to stumble across Eubayanus
Geraldine Butler, University College Dublin
However, most beer these days is made from lager, not ale, and there is much interest in understanding the historical transition from one to the other.
Lagers are fermented using bottom-fermenting yeast at cooler temperatures, while ales are fermented with a top-fermenting yeast at much warmer temperatures.
Lager brewing, which first appeared in Bavaria in the 13th century, uses a different species of yeast, Saccharomyces pastorianus.
It is a hybrid of two parents, only one of which is S. cerevisiae.
The identity of the second parent remained a mystery until 2011, when Saccharomyces eubayanus was discovered in the Patagonian Andes of South America.
Like S. pastorianus, S. eubayanus is cold-tolerant.
Although records show that the first use of S. pastorianus was in a brewery in southern Germany, the parent of S. eubayanus was never found in Europe.
Instead, researchers have discovered yeast in South America, North America, China, Tibet and New Zealand.
It surprised some researchers that S. Whether Eubaynus was ever actually in Europe, and if not, lager East S. Where does Pastorianus come from?
But now researchers at University College Dublin have discovered S. Discovered and isolated Eubyanus.
The researchers isolated two different S. Eubianus isolated the strain, as part of an undergraduate research project to identify wild yeasts and sequence their genomes.
The samples come from soil at two sites approximately 17 meters apart on the university campus, collected in September 2021.
According to the study, the genome sequence of these two isolates showed that they were ancestral to S. eubianus strains associated with primarily S. pastorianus was combined with S. cerevisiae to form
Researchers say that S. in Ireland. The discovery of Eubayanus shows that this yeast is native to Europe and seems to have lived in other parts of the continent.
This new research supports the view that there was a natural population of yeast in southern Germany in the Middle Ages and that it provided the first lager yeast parents.
Lead author of the paper, Geraldine Butler, University College Dublin, said: “This discovery is a great example of research-led education.
“Our undergraduates have found hundreds of yeast species in Irish soil samples over the past five years, and we have S. Delighted to stumble across Eubayanus.
“We’re hoping to find a commercial partner to build with it so we can find out what it tastes like.”
The research is published in FEMS East Research.