Initial abiotic factors as key drivers in core microbe assembly: Regulatory effects on flavor profiles in light-flavor Baijiu

Instability in initial abiotic factors of open solid-state fermentation systems can significantly alter Baijiu 's flavor profile, but the mechanisms governing microbial interactions and flavor formation remain unclear. This study comprehensively monitored changes in abiotic factors, microbial communities, and flavor profiles across two distinct fermentation processes in a Baijiu distillery, which differed significantly in their management of initial abiotic factors. Our results revealed significant differences in abiotic factors between the two groups, including moisture, ethanol, acidity, glucose, and organic acid levels. The assembly of microbial communities in fermented grains was primarily driven by deterministic processes. The moisture content in the fermentation grains positively affected the growth and metabolism of core microbiota. The rapid proliferation and metabolism of core microbes led to a rapid increase in the acidity of the fermented grains, alongside a significant accumulation of ethyl lactate. This study provides technical support and theoretical guidance for Baijiu production. • Initial abiotic factors-induced deterministic processes drive microbiota assembly in Baijiu fermentation. • Higher initial moisture in fermented grains enhances microbial growth and succession. • Lactobacillus leads to a rapid increase in the acidity of the fermented grains and substantial accumulation of ethyl lactate.