College of Tobacco Science/Tobacco Harm Reduction Research Center, Henan Agricultural University, No. 95 Wenhua Road, Zhengzhou, 450002, Henan, China.
Deyang Branch of Sichuan Tobacco Company, Deyang, 618000, Sichuan, China.
Curr Microbiol. 2023 May 19;80(7):218. doi: 10.1007/s00284-023-03314-z.
Tobacco mildew and tobacco-specific nitrosamines (TSNAs) affect the quality of tobacco products during fermentation. Microbes are thought to play key roles in the development of specific properties of fermented tobacco; however, little is known about the bacteria involved in the fermentation process. This study aims to identify key microbes related to mildew and TSNA formation. Tobacco was fermented at 25 °C, 35 °C, and 45 °C for 2, 4, and 6 weeks, with unfermented samples used as controls. Our preliminary exploration found that TSNAs content elevated with the increase of temperature and period, and mildew was easy to occur at low temperature with short period. Hence, samples were divided into three groups: the temperature gradient group (25 °C, 35 °C, and 45 °C for 6 weeks); the low-temperature group (control, 25 °C for 2, 4, and 6 weeks); and the high-temperature group (control, 45 °C for 2, 4, and 6 weeks). After collecting fermented tobacco leaves, 16S rRNA gene sequencing was used to explore the structure and dynamic changes of bacterial community during fermentation. Methylobacterium and Deinococcus were shared between the temperature gradient and high-temperature groups and showed a linear downward trend; these might play a role in the production of TSNAs. Massilia, Ruminiclostridium, and Cellulosilyticum species increased with prolonged fermentation time in the low-temperature group; this might be associated with tobacco mildew. In summary, the microbial diversity of fermented tobacco was explored under different conditions. These findings might provide data and material support to improve the quality of fermented tobacco products; however, further omics based studies are warranted to analysis the gene and protein expression patter in the identified bacteria.
烟草霉变和烟草特有亚硝胺（TSNAs）会影响发酵过程中烟草制品的质量。人们认为微生物在发酵烟草特有性质的发展中起着关键作用；然而，对于参与发酵过程的细菌知之甚少。本研究旨在确定与霉变和 TSNAs 形成相关的关键微生物。将烟草在 25°C、35°C 和 45°C 下发酵 2、4 和 6 周，以未发酵的样品作为对照。我们的初步探索发现，TSNAs 含量随着温度和时间的增加而升高，而霉变在低温短时间内更容易发生。因此，样品分为三组：温度梯度组（25°C、35°C 和 45°C 发酵 6 周）；低温组（对照，25°C 发酵 2、4 和 6 周）；高温组（对照，45°C 发酵 2、4 和 6 周）。收集发酵后的烟叶后，采用 16S rRNA 基因测序技术探索发酵过程中细菌群落的结构和动态变化。温度梯度组和高温组共有甲基杆菌属和异常球菌属，呈线性下降趋势；这些可能在 TSNAs 的产生中发挥作用。低温组中，随着发酵时间的延长，甲基球菌属、瘤胃球菌属和纤维分解菌属的数量增加；这可能与烟草霉变有关。综上所述，在不同条件下探索了发酵烟草的微生物多样性。这些发现可能为提高发酵烟草制品的质量提供数据和物质支持；然而，需要进一步进行基于组学的研究来分析鉴定细菌中的基因和蛋白质表达模式。
