A comparative analysis of the microbiome of cigars produced in the Caribbean and China

Abstract

Fermentation of cigar tobacco leaves involves intense microbial activity, and hence, microorganisms have a significant impact on the quality and flavour of cigars. However, research on the correlation between microbial communities and the sensory quality of cigars remains inconclusive. In this study, a comparative analysis of the microbial profiles of five Caribbean- and five Chinese-produced cigar products was conducted to reveal significant differences in the microbiome of cigars from two origins, potentially accounting for the variance in their quality and flavour. Our findings indicated that Chinese cigars supported a more diverse array of microorganisms compared to Caribbean counterparts, as evidenced by higher indices of α and β diversity. High-throughput sequencing revealed that the genus Staphylococcus was predominant in Caribbean cigars, representing over half of the bacterial population. In contrast, Staphylococcus comprised approximately 30% of the bacterial community in most Chinese cigar samples. Furthermore, a clear distinction of function prediction between Caribbean and Chinese cigars implied chemical biotransformation of cigar tobacco leaves under the influence of microbial communities. Subsequent comprehensive statistical analysis of the correlation between the microbiome and sensory quality of cigars suggested that certain bacterial species may be critical in shaping the flavour profile of cigars. Together, these insights indicated that the core microbiome of Caribbean and Chinese cigars was different, with each product exhibiting its characteristic bacterial genera. The unique genera presented in the core microbiome of Caribbean cigars could provide a novel perspective on the bioaugmentation fermentation of Chinese cigars.

Keywords: Bioaugmentation fermentation; Cigar; High-throughput sequencing; Microbial community; Sensory evaluation.

Fig. 1

Diagrams of α and β diversity analysis of grouped cigar samples. Indices of α diversity, (a) Chao 1 index, (b) ACE index, (c) Shannon index, (d) Simpson index. Indices of β diversity, (e) NMDS and (f) PCoA between Caribbean and Chinese cigar products, (g) NMDS analysis of within-sample diversity among each product of Caribbean and Chinese cigar products. In a to f, coral color represents Caribbean cigars, while turquoise color represents Chinese cigars.

Fig. 2

Comparisons of the core microbiota between Caribbean and Chinese cigars. Stacked bar graphs representing the relative abundance of the top 10 genera across Caribbean (a) and Chinese cigars (b). Venn diagrams show the number of unique and shared genera in the core microbiome of each product of Caribbean cigars (c) and Chinese cigars (d), as well as Caribbean vs. Chinese cigars (e).

Fig. 3

Statistical results of LEfSe analysis. In cladograms (a for comparison between Caribbean and Chinese, and b for comparison among each product), the circles radiating from the inside to the outside represent the classification level from class to genus. Each small circle at a different classification level represents a classification at that level, and the diameter of the small circle is proportional to the relative abundance. Colouring principle: biomarkers with no significant differences were uniformly in white, and the biomarkers were coloured according to the group. LDA value distribution bar graphs (c for Caribbean vs. Chinese and d for comparison among each product) show biomarkers with statistical differences between groups (LDA scores ≥ 4). The length of the bar chart represents the impact size of each taxon.

Fig. 4

Functional differences of microbial communities on cigars using PICRUSt2. Venn diagrams presenting unique and shared core pathways in microbial communities of Caribbean (a) and Chinese (b) cigar products. Clustered heatmaps of the relative abundance of the top 35 pathways in Caribbean cigars (c) and Chinese cigars (d). On the left side of heatmaps is the functional clustering tree. The value corresponding to each block was the Z value of each row of the pathway, representing the standardized relative abundance. (e) Venn diagram showing unique and shared core pathways among cigars from different regions.

Fig. 5

The correlation between microbial communities and sensory quality using Spearman correlation analysis. The correlation in Caribbean and Chinese cigars combined (a), Caribbean cigars (b), and Chinese cigars (c). A p-value less than 0.05 was regarded as statistically significant and labelled with an asterisk.