New lager yeast strains generated by interspecific hybridization

Area of Science:

• Microbiology
• Yeast Genetics
• Fermentation Science

Background:

• Saccharomyces pastorianus, the lager yeast, is crucial for global brewery fermentations.
• Understanding the genetic basis and creation of lager yeast strains is vital for the brewing industry.

Purpose of the Study:

• To generate novel de novo lager yeast hybrids through interspecific hybridization.
• To characterize these hybrids for desirable brewing traits, including cryotolerance and fermentation performance.
• To explore the potential of hybridization for developing new non-genetically modified (non-GM) lager yeast strains.

Main Methods:

• Interspecific hybridization by mating Saccharomyces cerevisiae (ale strain) with Saccharomyces eubayanus.
• Wort fermentation at 12 °C to mimic lager brewing conditions.
• Analysis of resulting beers for sugar and aroma compounds.
• Assessment of yeast flocculation ability and alpha-glucoside transport capability.

Main Results:

• Hybrids demonstrated cryotolerance, maltotriose utilization, and strong flocculation, inheriting traits from both parents.
• Observed hybrid vigor, with faster fermentation rates and higher alcohol content (5.6% ABV) compared to parent strains (4.5% ABV).
• Successful characterization of novel lager yeast hybrids with unique properties.

Conclusions:

• Interspecific hybridization is a viable strategy for producing novel, non-GM lager yeast strains with desirable industrial properties.
• The generated hybrids possess beneficial traits for lager brewing, including improved fermentation efficiency and cryotolerance.
• This research contributes to understanding the evolutionary history of industrial lager yeasts.