Interrelated spatiotemporal variations between bacterial community and physicochemical factors in pit mud of Chinese strong-flavor Baijiu

The spatiotemporal variations of bacterial communities and physicochemical factors in pit mud of Chinese strong-flavor Baijiu from Jinhui Liquor (Longnan, Gansu) were investigated. The temporal heterogeneity of bacterial communities and physicochemical properties was more significant than the spatial. The majority of physicochemical indexes in the new (5, 7, and 10-year) PM significantly differed from that of the old (30 and 50-year) PM. Combined with the microbiome characteristics, the main factors affecting the bacterial community composition included pH, humus, moisture, available P, NH4+-N, capric, lactic, and acetic acid. The new and old PMs were clearly distinguished based on microbiome, and the species evenness in the old PM was higher. The p_Proteobacteria, p_ Acidobacteria, Lactobacillus, Pseudomonas, and Hydrogenophaga were more abundant in new PM with a range of 1.72%–42.73%, while the p_Firmicutes, p_Bacteroidetes, Petrimonas, Clostridium, and Caloramator were dominant in the old PM (4.09%–52.54%). The metabolic activity of other amino acids, lipid, and xenobiotics was higher in the new PM, while amino acid, carbohydrate, cofactors, and vitamins were higher in old PM. According to model fitting on the community assembly, the bacterial community construction depended on the stochastic process (|βNTI|≤2). This work provides a reference for the cultivation of high-quality PM in liquor brewing.