16S rRNA gene amplicon analysis of bacterial community structure in Huangshui, a fermentation by-product from Chinese strong-flavor Baijiu production

Huangshui (yellow water) is a naturally fermented liquid by-product collected from the bottom of mud cellars during the production of Chinese strong-flavor Baijiu. Formed by moisture percolation through fermented grain and pit mud, this acidic and nutrient-rich effluent serves as a unique reservoir of microbial diversity, harboring metabolically active bacterial communities that are essential for flavor compound formation during the fermentation process. Huangshui contains residual ethanol, organic acids, sugars, and amino acids, creating a selective environment for specialized microbial functional groups.