Driving impact of organic acids on microbial community dynamics and fermentation performance in Huangjiu

Huangjiu, a traditional Chinese rice wine, relies on microbial communities for its quality, but the role of organic acids during fermentation is unclear. This study uses flavoromics and metatranscriptomics to explore how organic acids shape microbial composition and metabolism. Comparing samples with high (H) and low (L) organic acid content, 44 flavor compounds were identified, revealing significant group differences. Organic acids altered fungal communities: succinic acid positively correlated with Saccharomyces and Thermomyces, while lactic and tartaric acids showed negative correlations. Simulated fermentations and sequencing demonstrated that succinic acid enhanced Saccharomyces cerevisiae growth, upregulated sugar-metabolism genes, and boosted ethanol production. Understanding endogenous organic acids' regulatory effects may inform potential approaches to modulate microbial community structure, optimize fermentation performance, and potentially improve Huangjiu flavor. These insights could provide a reference for precision fermentation management in similar traditional beverage systems, pending further validation.