Abstract: Our laboratory had isolated a strain of non-Saccharomyces yeast with significant application potential from high-temperature Daqu, Lachancea thermotolerans Y-07. This study aimed to explore the interaction of L. thermotolerans Y-07 with Aspergillus oryzae M-08 and Saccharomyces cerevisiae BS-19 when used for mixed culture fermentation of Baijiu under gradient temperature conditions and to evaluate its impact on Baijiu quality. To this end, changes in biomass, sensory quality, organic acids and volatile flavor compounds were examined during the fermentation process. The results demonstrated that L. thermotolerans Y-07 produced β-phenylethanol, reduced the higher alcohol content, and significantly improved the sensory quality of Baijiu, indicating its positive role in Baijiu brewing. High-temperature conditions not only helped maintain yeast diversity during the fermentation process, but also enhanced aroma richness. The presence of S. cerevisiae BS-19 increased the biomass of L. thermotolerans Y-07 by 21.63%. Under high-temperature conditions, the presence of S. cerevisiae BS-19 facilitated the recovery and proliferation of L. thermotolerans Y-07. This study provides important insights into the mechanism of action of L. thermotolerans in Baijiu brewing and the influence of temperature on microbial interactions during the fermentation process.

Key words: Baijiu fermentation, Lachancea thermotolerans, mixed culture fermentation, microbial interaction, flavor quality