Selective Breeding of Saccharomyces Wine and Beer Strains to Enhance Aromatic Diversity in Beverage Fermentation

This study investigates the breeding of the German wine yeast Oppenheimer Kreuz 1894, which carries a FOT1 allele of a fungal oligopeptide transporter, with Freya, a Kveik ale yeast, to enhance fermentation performance and aroma in beer and wine. By combining Kveik traits (osmotolerance, thermotolerance, and rapid fermentation kinetics) with those of a German wine yeast (ethanol tolerance, broadened nitrogen utilization, and aroma production) and introducing FOT1 into an ale background via classical breeding, we aimed to leverage the Saccharomyces biodiversity to improve fermentation activity and expand aromatic complexity. Fermentation products and volatile aroma compounds were quantified by HPLC and HS-SPME-GC-MS. Spore clone derivatives of initial hybrid strains (F2-generation) showed improved fermentation profiles with increased CO2 production. In wine fermentations, the best-performing spore clone, GYBC 901, yielded a rich aromatic profile with elevated fruity and floral notes. In beer fermentations, GYBC 899 produced the most diverse and complex aroma. FOT1 was of minor relevance to the breeding outcome, whereas meiotic recombination generated a set of diverse spore clones. These results highlight the potential of strategic yeast breeding to optimize fermentation processes and tailor flavor profiles to diverse product targets. Future work will elucidate metabolic pathways underlying these phenotypes and advance the development of application-specific strains, offering avenues to enhance beverage quality and product differentiation in the fermentation industry.