Exploring the Ecological Interactions of Bacillus and Their Contribution to Characteristic Aroma Components in Zhenjiang Aromatic Vinegar

Zhenjiang aromatic vinegar (ZAV), known for its distinctive flavors, is produced through traditional solid-state fermentation involving multiple strains. The development of functional microbial communities during repeated batch acetic acid fermentation (AAF) is crucial for flavor formation in ZAV. Hence, investigating the two pivotal factors, namely flavor synthesis and microbial strains, within the vinegar ecosystem is essential for the vinegar industry to modulate the metabolic function of vinegar microbiota, monitor the fermentation process, and maintain the desired flavor quality of the final product. This study aimed to explore the ecological interactions of Bacillus within the vinegar Pei and examine the correlation between the Bacillus community and the characteristic aroma components of ZAV. The findings demonstrated that the dynamic of Bacillus community was drove by environmental factors represented by temperature and acidity, together with the interactions between microorganisms. Moreover, Bacillus exhibited a significant positive correlation with 34 volatile flavor components, including 7 alcohols, 1 acid, 20 esters, 3 aldehydes, 2 ketones, and 1 phenol. The characteristic aroma components strongly associated with Bacillus were identified as lactic acid, six ethyl esters, namely ethyl acetate, benzeneacetaldehyde, and 3-methylbutyraldehyde. Overall, this study revealed the crucial role of Bacillus in maintaining fermentation system stability and facilitating flavor synthesis. The detailed insights provided here contributed to a better understanding of the fermentation mechanisms underlying ZAV.