Exploring Non-Saccharomyces yeasts from Daqu for beer production

Daqu is an essential component in the solid-state fermentation of Chinese Baijiu, and non- Saccharomyces yeasts from Daqu significantly contribute to the complex flavors in Baijiu . However, the potential of non- Saccharomyces yeasts from Daqu in beer production has remained unexplored. In this study, 80 strains representing 14 non- Saccharomyces yeast species were isolated from various Daqu . These strains were scrutinized for their stress tolerance, flocculation, fermentation performance, and the production of flavor compounds. Subsequently, representative strains were chosen for beer production, and the resulting products from both single- and mixed-strain fermentations underwent sensory evaluation. Toruaspora delbrueckii TD2 exhibited excellent fermentation properties in wort. In compared to US-05, the non- Saccharomyces yeast strains tested significantly increased volatile favor compounds. Notably, the Wickerhamomyces anomalus strain showed a 13.86-fold increase in ethyl acetate production, while the Hanseniaspora osmophila strain displayed a 7-fold increase in phenylethyl acetate production. Co-fermentations of these strains with US-05 did not impact attenuation and ethanol concentration but significantly enhanced aromatic profiles. This study offers valuable insights into the fundamental attributes and brewing potential of non- Saccharomyces yeasts sourced from Daqu , broadening the spectrum of yeast selection for the creation of innovative beers. • Non- Saccharomyces yeasts from Daqu were isolated and evaluated for beer brewing. • Wickerhamomyces anomalus produces 13.86 times more ethyl acetate than US-05. • Hanseniaspora osmophila fermentation was 7-folds increase in phenylethyl acetate. • Non- Saccharomyces significantly enhance aromatic esters in mixed-fermentation with S. cerevisiae. • Mixed-fermentation could produce fruity-like beer between H. osmophila and T. delbrueckii.