Synergistic Effect Enhances Aromatic Profile in Beer Brewing Through Mixed-Culture Fermentation of <i>Pichia kluyveri</i> and <i>Saccharomyces cerevisiae</i> var. <i>diastaticus</i>

<i>Saccharomyces cerevisiae</i> is one of the important species of traditional fermented foods and beverages. However, incorporating non-<i>Saccharomyces</i> in the fermentation process is a promising strategy to improve the organoleptic profile. In this study, we assessed the potential of a wild <i>Pichia kluyveri</i> strain (PKL) to augment the aromatic profile in beer brewing while maintaining high fermentation attenuation through inoculation with <i>Saccharomyces cerevisiae</i> var. <i>diastaticus</i> yeast (SY) in both simultaneous (SI-PKL/SY) and sequential (SE-3-PKL/SY) approaches. The fermentation performance was analyzed by residual sugar content, volatile organic compounds, and sensory evaluation. The results indicated that both co-fermentation methods yielded residual sugar levels comparable to those of SY monoculture fermentation. The 2-phenethyl acetate, isoamyl acetate, and linalool in SE-3-PKL/SY increased 12.00, 12.37, and 1.17 folds than the SY monoculture, respectively. Furthermore, the incremental concentrations of these compounds contributed to the highest acceptability and prominent fruity notes in the SE-3-PKL/SY coculture. The current study is the first to report on the co-fermentation with <i>Pichia kluyveri</i> and <i>Saccharomyces cerevisiae</i> var. <i>diastaticus</i> in beer brewing. These findings highlighted the importance of <i>Pichia kluyveri</i> in shaping the ameliorative aroma profile of fermentation production.