Temporal heterogeneity of microbial ecosystems and its formation mechanisms in Moutai-flavor Baijiu fermentation

The influence of workshop age on Moutai-flavor Baijiu fermentation is recognized, but the mechanisms driving microbial community shifts remain unclear. Understanding how the physical environment selects for specific microbiota is crucial for optimizing new workshops. Through 16S/ITS sequencing of pit-entry fermented grains, Daqu, air, and cooling yards in 5-, 10-, 20-, and 30-year-old workshops, Lactobacillus emerged as a key discriminant genus, increasing from 15.02% (5-year) to 35.59% (30-year). SourceTracker analysis revealed the cooling yard as the primary microbial source, contributing 54.2% on average to fermented grains. CO 2 -TPD analysis showed a 3.6-fold reduction in cooling yard surface basicity (from 0.11 to 0.03 mmol·g −1 ) over 30 years, resulting in high abundances (>10%) of alkalotolerant bacteria (e.g., Alkalibacterium , Nesterenkonia ) and low Lactobacillus (2.17%). Nesterenkonia was also a biomarker in 5-year fermented grains. This confirms cooling yard surface basicity drives microecological differences, revealing how long-term production practices domesticate microbial communities and providing a theoretical basis for new workshop adaptation.