Isolation and evaluation of a Bacillus altitudinis strain to improve cigar tobacco leaves fermentation

Hejun Liu¹Xin Fang^1,2Shiping Guo³Bo Zhang¹Chongde Wu^1,2Qiu Zhong⁴Ruina Zhang⁴Hongzhi Shi⁵Yanqing Qin^3*Shuhua Zeng^6*Yao Jin^1,2*

• ¹Sichuan University College of Biomass Science and Engineering, Chengdu, China
• ²Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
• ³Sichuan Provincial Branch of China National Tobacco Crop Tobacco Science Institute, Chengdu, China
• ⁴Deyang Tobacco Company of Sichuan Province, Sichuan, Deyang, China
• ⁵Henan Agricultural University School of Tobacco Science, Zhengzhou, China
• ⁶Sichuan Agricultural University College of Agronomy, Chengdu, China

This study explores a core functional strain to enhance the fermentation of premium cigar tobacco leaves. A tobacco extract-based solid medium enabled the isolation of 65 bacterial strains, of which 16 exhibited notable proteolytic activity. Bacillus altitudinis (CCTCC M20211370) with superior protein-degrading capacity, was selected for application. Inoculated fermentation with such strain significantly elevated aromatic compounds such as neophytadiene and β-ionone, while reducing nicotine and myosmine content. The strain also reshaped microbial community succession of tobacco fermentation. GC-MS profiling revealed dynamic transitions in volatile metabolites and their associations with dominant taxa. These results demonstrate the functional potential of Bacillus altitudinis in regulating microbial ecology and enhancing aroma development during cigar tobacco fermentation, offering a theoretical basis for bioaugmentation and process refinement in the cigar industry.