Temperature-associated microbial succession and volatile flavor compound dynamics during cigar tobacco leaf fermentation

Temperature is a key factor driving microbial community succession and volatile flavor compound formation during the fermentation of cigar tobacco leaves (CTLs). This study systematically investigated microbial community dynamics, co-occurrence networks, and volatile flavor compound (VFCs) profiles of CTLs from Dominica and Yunnan under a 20–60 °C fermentation gradient. High-throughput sequencing identified Staphylococcus, Oceanobacillus, and thermophilic fungi as core microbes potentially associated with aroma formation. Dominica CTLs exhibiting higher microbial diversity than Yunnan CTLs. Dominica CTLs produced abundant esters, alcohols and ketones across different temperature stages, whereas Yunnan CTLs accumulated more pyrazines, indole and terpenoids at high temperatures (≥ 50 °C). Co-occurrence network analysis revealed temperature-driven shifts in microbial interactions: Dominica CTLs formed balanced networks with mixed positive/negative correlations at low temperatures, while Yunnan CTLs developed stable networks dominated by positive correlations at high temperatures. PERMANOVA indicated significant differences in microbial community structure among temperature gradients (R2 = 0.78, p < 0.001). Spearman correlation analysis suggested that core microbes (e.g., Staphylococcus) were significantly correlated with the accumulation of key VFCs (e.g., esters, alcohols). These findings propose a conceptual temperature–microbe–VFC interaction framework, providing theoretical support for optimizing CTL fermentation processes.