Seasonal dynamics, assembly mechanisms, and implications of the distillery workshop microbiota for strong-flavor...

The production environment serves as a critical microbial reservoir that shapes the quality and stability of spontaneously fermented foods, yet the ecological rules governing its resident communities remain unclear. Through two-year monitoring of four core workshop habitats (indoor air (IA), equipment surface (ES), ground, and wall) in a strong-flavor Baijiu distillery, this study elucidated the spatiotemporal assembly of environmental microbiota. We identified ten fermentative genera, including Bacillus and Aspergillus, as the dynamic and stable core taxa across all habitats. Community assembly was dominated by stochastic processes, with dispersal limitation accounting for 48.64%-87.17% of the ecological dynamics. Interaction networks exhibited habitat-specific architectures, IA network displayed the highest complexity and modularity. Source tracking revealed the fermentation system as the main source of environmental microbes. Notably, eight genera, including Kroppenstedtia and Thermoactinomyces, were specifically enriched in IA. Partial least-squares path model further demonstrated that fungal communities were markedly more sensitive than bacteria to environmental factors, particularly the workshop's years of use and habitat type. Collectively, this work redefined the production workshop as a dynamically assembled microbial ecosystem. By analyzing the assembly patterns of the environmental microbiota and the driving environmental factors that drive them, it identifies potential control points that could inform future efforts to modulate microbial communities and manage the "microbial terroir". These findings lay a theoretical foundation for stabilizing product quality and for advancing traditional fermentation toward a more scientific and controllable production.