Project start: 01.01.2026
Project end: 31.12.2026
Sponsor: Wissenschaftsförderung der Deutschen Brauwirtschaft e.V.

This project continues the fundamental research on brewer's yeast breeding, building on the successful preliminary project B113. That project demonstrated that yeast breeding with lager yeasts used for pilsner beer production is extremely difficult and time-consuming. These yeasts have largely lost their ability to reproduce sexually due to centuries of domestication. The hybrid nature of these yeasts further complicates matters. Modern lager yeasts originate from hybridization between a S. cerevisiae ale yeast and a S. eubayanus yeast. Subsequent domestication has led these yeasts of the Saaz and Frohberg groups into a breeding dead end. In the previous project, we were able to obtain spore clones from the subsequently germinated spores via sporulation. These spore clones from Frohberg yeasts, such as the Weihenstephan W34/70 lager yeast, showed that they retained their hybrid character. This is not desirable for breeding purposes. Better results have been achieved with spore clones from ale yeasts. These have produced stable, haploid, heterothallic lines that are ideally suited for further breeding (Badura et al., 2025). The new project aims to advance the breeding of new lager yeasts. In addition to the existing groups of lager yeasts, especially Saaz and Frohberg yeasts, new variants will be developed. The production of stable haploid cell lines plays a crucial role in this, as such strains greatly simplify breeding approaches.