Systematically exploring and evaluating core fungal composition and their flavor profile in fermented grains of Jiang-flavor baijiu

Fungi play critical roles in the production of flavors during pit fermentation. To date, however, knowledge regarding core fungi in JFB remains limited. This study aimed to identify core fungi and evaluate their fermentation performance. Based on criteria including abundance, distribution range, interaction strength, and flavor-producing capacity, <i>Zygosaccharomyces</i>, <i>Aspergillus</i>, <i>Millerozyma</i>, and unclassified <i>Dipodascaceae</i> were identified as core fungi. Dominant species <i>A. niger</i> m6 and <i>Z. pseudobailii</i> J71 exhibited high metabolic activities. Co-culture systems of <i>Saccharomyces cerevisiae</i> J73 with <i>Z. pseudobailii</i> (SZ 1:10) and with <i>A. niger</i> (SA 1:0.1) enhanced the production of alcohols, acids, and esters. Compared with D35, the contents of certain flavor compounds were significantly higher in the SA and SZ co-culture systems. Collectively, this study firstly provides comprehensive exploration and evaluation of core fungi in JFB, establishing a preliminary foundation for constructing synthetic microbial communities and elucidating microbial interaction mechanisms during the production of baijiu flavors.