Mechanisms of Fermentation Quality improvement of Cigar Wrapper Leaves Inoculated with Exogenous Strain Staphylococcus capitis S1

To study the effects of the exogenous strain S1 on aroma and quality of CWLs during fermentation, as well as the resulting changes in the microbial community, volatile aroma components in CWLs were analyzed and evaluated at four fermentation stages using GC-MS. After inoculating the exogenous strain S1, the levels of compounds such as Phenethyl alcohol, Dihydroactinidiolide, Sclareol, and FARNESYL ACETONE in the CWLs were significantly upregulated compared to the pre-fermentation(NF) and natural fermentation with only water groups. Notably, the content of Phenethyl alcohol increased by 261.63% compared to the same turning period in the WF group, and FARNESYL ACETONE increased by 144.99%. The proportion of major chemical components showed that the proportion of carbohydrates and nicotine significantly increased after the inoculation of S1. Additionally, microbial samples from the surface of CWLs collected at the four fermentation stages were subjected to metagenomic analysis. The results showed that the inoculation of the exogenous strain S1 significantly improved the microbial community structure on the surface of the CWLs and led to significant differences in the microbial populations. After inoculation, at the phylum level, the proportion of Pseudomonadota increased dramatically to 17%, while the proportion of Uroviricota sharply decreased from 9% to 0%. At the genus level, the microbial community shifted from a single Staphylococcus genus before fermentation to a diverse community including genera such as Pantoea, Enterobacter, Cronobacter, and Aspergillus, resulting in a more balanced microbial composition that promotes the quality enhancement of CWLs.