OCT 23, 2015 10:27 AM PDT

Domestication of Lager-Brewing Yeasts

WRITTEN BY: Sarah Hertrich
According to Benjamin Franklin “Beer is the proof that God loves us and wants us to be happy.” I am sure many of us agree since beer making has become a large industry, producing more than 100 gallons of beer per day worldwide. In the United States alone, $101.5 million in beer sales and $19.6 billion in craft beer sales was reported by the Brewers Association. The essential ingredients of beer include hops, water, malt, and yeast. Hops provide flavor and antimicrobial activity. Malt serves as a carbohydrate for the yeast. Yeast, most importantly, produces alcohol and carbon dioxide. Yeasts are microorganisms that raise, ferment, carbonate and transform a wide variety of products related to food and agriculture, including beer.
Yeasts that are used to ferment lager-style beers today are examples of highly successful, domesticated interspecies yeast hybrids.

Different species of yeast are used to produce different types of beer, such as ales and lagers. Saccharomyces cerevisiae is a yeast that grows on top of the beer mixture (known as a top-fermenter) and is used to produce ales. S. cerevisiae is also the yeast used to make bread. Saccharomyces carlsbergensis is a yeast that settles to the bottom of the beer mixture (known as a bottom fermenter) and was the yeast previously known to produce lagers.  

Yeasts that are used to ferment lager-style beers today are examples of highly successful, domesticated interspecies yeast hybrids. Hybrid lager strains account for 94% of the world lager brewing market. In the 1980s, the lager yeast typically referred to as S. carlsbergensis was determined to actually be an interspecies hybrid of S. cerevisiae and a second parental species. It has been hypothesized that this other parental strain is Saccharomyces eubayanus, described as an independent species in 2011 in association with Nothofagus trees in Patagonia.

A study published this month in Molecular Biology and Evolution by researchers at the University of Wisconsin and INIBIOMA in Argentina compared the genome of S. eubayanus to the genome of multiple domesticated yeast hybrids including the hybrids of S. eubayanus x S. cerevisiae currently used to ferment lager-style beers. Researchers found that S. eubayanus subgenomes had previously undergone a strong shift in selection regimes. This selection showed to be consistent with the domestication of the S. cerevisiae parent prior to hybridization.
S. carlsbergensis was determined to actually be an interspecies hybrid of S. cerevisiae and S. eubayanus.

Their results showed that the radically different genomes of the two lager species lineages favors at least two independent lineages for the S. eubayanus x S. cerevisiae hybrids used to producer lager style beers. These results show how this industrially important yeast hybrid has been domesticated along similar evolutionary pathways on multiple occasions.

Sources: Molecular Biology and Evolution; Food Microbiology (3rd Edition); Brewers Association
 
About the Author
  • I am a postdoctoral researcher with interests in pre-harvest microbial food safety, nonthermal food processing technologies, zoonotic pathogens, and plant-microbe interactions. My current research projects involve the optimization of novel food processing technologies to reduce the number of foodborne pathogens on fresh produce. I am a food geek!
You May Also Like
DEC 14, 2020
Cell & Molecular Biology
Modeling Embryonic Development in the Laboratory
DEC 14, 2020
Modeling Embryonic Development in the Laboratory
Max Planck Institute for Molecular Genetics researchers have created a model that will advance the study of development ...
DEC 16, 2020
Cell & Molecular Biology
A Close Connection Between Two Organelles is ID'ed
DEC 16, 2020
A Close Connection Between Two Organelles is ID'ed
The cell has many specialized components that perform specific functions, like an organelle called the endoplasmic retic ...
JAN 10, 2021
Microbiology
Some Bacteria Know the Time
JAN 10, 2021
Some Bacteria Know the Time
People, animals, and even plants are known to have biological clocks, and new work has revealed that free-living bacteri ...
JAN 20, 2021
Microbiology
Cannabis Compound Could Lead to New Class of Antibiotics
JAN 20, 2021
Cannabis Compound Could Lead to New Class of Antibiotics
For the first time, a synthetic version of a non-psychoactive molecule found in marijuana has been shown to kill pathoge ...
FEB 04, 2021
Microbiology
Using Synthetic Biology to Reimagine Development
FEB 04, 2021
Using Synthetic Biology to Reimagine Development
Scientists have been able to grow Escherichia coli bacteria colonies in complex shapes that E. coli doesn't typically fo ...
FEB 08, 2021
Genetics & Genomics
Human Epigenome Map Reveals Genetic Circuitry
FEB 08, 2021
Human Epigenome Map Reveals Genetic Circuitry
While the human genome was sequenced many years ago, there was so much to learn about it beyond just its sequence, like ...
Loading Comments...