Non-GMO Maltotriose-Consuming Strains of Saccharomyces Eubayanus

Chris Hittinger, EmilyClare Baker

Saccharomyces eubayanus is the cold-tolerant parent yeast of the lager brewing yeast Saccharomyces pastorianus. In recent years there has been considerable interest in brewing with pure strains of S. eubayanus. However, all known wild strains lack the ability to consume maltotriose. Therefore, beers produced with pure S. eubayanus retain a sweet taste and remain low in alcohol content, two traits that are undesirable for commercial success.

The Invention

UW-Madison researchers have produced maltotriose-consuming strains of pure S. eubayanus by repeatedly passaging wild strains for hundreds of generations in 0.1% glucose and 2% maltotriose, or 2% maltose. After directed evolution, some strains evolved the ability to consume maltotriose as the sole carbon source. This trait has been shown by the researchers to be stable and genetically heritable, and it is likely encoded by a single genetic locus.

Key Benefits
  • These strains are descendants of the wild S. eubayanus strain that is the closest relative of the lager yeasts.
  • No pure strains of S. eubayanus that consume maltotriose exist
  • Novel brewing yeast that is cold-tolerant


Technology Contact

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