Milky flavor-producing Bacillus subtilis and its application in cigar tobacco leaves

LI Tianxiao; ZHANG Dayuan; WANG Yue; LEI Jinshan; CAO Yuan; XU Chunping; ZHANG Qianying; LI Dongliang

doi:10.12187/2025.02.010

Abstract：In order to solve the problems of poor aroma and strong irritation of Sino-cigar tobacco leaves,milky flavor-producing microbial strain isolated from tobacco leaves was screened through smell evaluation in this study.The bacterium was identified by microscopic characteristics and 16S rDNA sequence analysis.The liquid fermentation conditions were optimized by sensory evaluation of flavoring in machine-made cigar and OD600 of bacterial turbidity.The key aroma components of the fermentation broth were determined by GC-MS analysis.Flavoring effects of the Bacillus strain on the sensory quality of cigar tobacco leaves were also studied.The results showed that one bacterium strain F2A was screened out,which was identified as B.subtilis.The preferred conditions for liquid fermentation were temperature of 32℃,time of 24 h,carbon sources of glucose,and inorganic salts of CaCl2.The main milky and sweet aroma component in the fermentation broth was identified as 2-hydroxy-3-methyl-2-cyclopentenone with a high content of 7.58 μg/mL.After fermentation by B.subtilis F2A,the contents of milky and sweet flavor components such as vanillin,coumarin,6-ethyl-5,6-dihydropyran-2-one,and 2-hydroxy-3-methyl-2-cyclopentenone in fermented Chexue 14 cigar tobacco leaves were significantly increased,which significantly enhanced milky and sweet aromas.And the enhancement of tabanone,3-hydroxy-β-damascone,and neophytadiene could improve freshness and floral smell.After fermentation,the milky and sweet aromas of cigars produced by Chexue 14 tobacco leaves were significantly improved,and the irritation was reduced.This study suggested B.subtilis F2A could produce 2-hydroxy-3-methyl-2-cyclopentenone and other flavor compounds,which provides a new way and theoretical support for the quality improvement of cigar tobacco leaves.