Changes in physicochemical properties and microbial community succession during leaf stacking fermentation

Abstract

Leaf stacking fermentation involves enzymatic actions of many microorganisms and is an efficient and environmentally benign process for degrading macromolecular organic compounds. We investigated the dynamics of metabolite profiles, bacterial and fungal communities and their interactions during fermentation using cigar leaves from three geographic regions. The results showed that the contents of total sugar, reducing sugar, starch, cellulose, lignin, pectin, polyphenol and protein in cigar tobacco leaves was significantly decreased during fermentation. Notably, the furfural, neophytadiene, pyridine, benzyl alcohol, geranylacetone, 3-hydroxy-2-butanone, N-hexanal, 3-Methyl-1-butanol and 2,3-pentanedione were important features volatile aroma compounds during fermentation. The α-diversity of fungi and bacteria initially increased and then decreased during fermentation. An analysis of variance showed that microbial diversity was influenced by fermentation stages and growing locations, in which the all stages had greater impacts on α- and β-diversity than all regions. Microbiome profiling had identified several core bacteria including Sphingomonas, Bacillus, Staphylococcus, Pseudomonas, Ralstonia, Massilia and Fibrobacter. Fungal biomarkers included Aspergillus, Penicillium, Fusarium, Cladosporium and Trichomonascus. Interestingly, the molecular ecological networks showed that the core taxa had significant correlations with metabolic enzymes and physicochemical properties; bacteria and fungi jointly participated in the carbohydrate and nitrogen compound degrading and volatile aroma compound chemosynthesis processes during fermentation. These studies provide insights into the coupling of material conversion and microbial community succession during leaf fermentation. Graphical abstract

Integrated characterization of filler tobacco leaves: HS–SPME–GC–MS, E-nose, and microbiome analysis across different origins

“…These findings are in concordance with the microbial patterns reported in H382 cigar leaves from Hainan (Liu et al 2021a ). Further corroborating our results, Zhang et al (Zhang et al 2023a ) documented the dynamic interplay of microbial communities during leaf stacking fermentation, highlighting their critical role in the transformation of macromolecules and the synthesis of distinctive volatile aroma compounds. The study also revealed that both the fermentation stage and geographic location influence microbial diversity, particularly impacting core taxa like Sphingomonas , Bacillus , Aspergillus , and Penicillium .…”

“…In addition to these chemical factors, the microbial community structure of tobacco leaves plays a crucial role in determining the quality and character of cigars. Microbial communities, consisting of a variety of bacteria and fungi, actively participate in the fermentation process, influencing the development of aroma compounds and the overall sensory profile of tobacco (Ning et al 2023a , b ; Zhang et al 2023a ). The diversity and dynamics of these microbial populations are closely linked to environmental factors such as climate, soil composition, and agricultural practices, varying in different tobacco-growing regions.…”

Effect of tobacco–radish rotation for different years on bacterial wilt and rhizosphere microbial communities

“…responses to environmental changes (Liu et al 2022;Zhang et al 2023). For example, studies have demonstrated that ecological networks composed of strong interactions are more stable than are ecological networks with weak interactions and that the presence of separations and interactions increases the stability of the network under disturbance (Wang et al 2021).…”