贝莱斯芽孢杆菌提升雪茄茄衣烟叶发酵品质机制研究

Study on the mechanism of improving fermentation quality of cigar wrapper leaves by Bacillus velezensis

为探究贝莱斯芽孢杆菌(Bacillus velezensis)对雪茄茄衣烟叶增香提质的作用机制,考查了茄衣烟叶在自然发酵和添加贝莱斯芽孢杆菌H1发酵(实验组)后常规化学成分、挥发性香气物质及微生物群落结构的变化及相关性,并对微生物的代谢途径变化进行分析。结果表明:与自然发酵相比,实验组茄衣烟叶的香气物质种类、常规化学成分(如烟碱、总氮和钾)与挥发性香气物质(如植物醇、香叶基丙酮和新植二烯)的相对含量均发生显著改变,烟气品质得以改善,烟气更醇和;相比自然发酵,实验组茄衣烟叶表面细菌多样性发生明显变化,OTU数目提高,茄衣烟叶优势菌门由厚壁菌门(Firmicutes)变为放线菌门(Actinobacteriota),优势菌属由单一的葡萄球菌属(Staphylococcus)转变为葡萄球菌属、闫逊初氏菌属(Yaniella)、未命名菌(unclassi-fied_f Micrococcaceae)等;优势菌属的改变使微生物代谢途径发生变化,前五种差异代谢途径分别为全局和总览图、碳水化合物代谢、氨基酸代谢、辅因子和维生素代谢和能量代谢;还原糖等常规化学成分受茄衣烟叶细菌群落的影响较大,苯乙醇的生成与葡萄球菌属、棒状杆菌属和海洋芽胞杆菌属等有关,香叶基丙酮的生成与藤黄微球菌属、海洋芽胞杆菌属和肠球菌属密切相关。

The differences and their correlation in conventional chemical composition,fragrance-causing components and microbial community structure of cigar wrapper leaves before and after fermentation as well as metabolic pathway change were analyzed in this study to explore the mechanism of B.velezensis H1 on the flavoring and quality enhancement of cigar wrapper leaves.The results showed that relative contents of nicotine,total nitrogen and potassium were significantly changed after adding exogenous B.velezensis H1.The types and the content of aroma substances in cigar wrapper leaves treated with B.velezensis H1 increased significantly,such as phytol,geranylacetone and neophytadiene,which could effectively improve the quality of flue gas to be pure and mild.After fermentation,the bacterial diversity on the surface of cigar wrapper leaves changed significantly,and the number of OTUs was increased after B.velezensis H1 inoculation.The bacterial community structure and dominant flora on the surface of tobacco leaves were changed.The dominant phylum changed from Firmicutes to Actinobacteriota after treated with B.velezensis H1.The dominant genus evolved from Staphylococcus to Staphylococcus,Yaniella,unclassified_f Micrococcaceae.The top five metabolic pathways of significant changes due to microbial community structure transformation were global and overview maps,carbohydrate metabolism,amino acid metabolism,metabolism of cofactors and vitamins,and energy metabolism.The results of correlation analysis showed that key substances such as reducing sugar,total nitrogen,nicotine,chlorine,total sugar,and potassium were greatly influenced by the bacterial community of cigar wrapper leaves.Generation of phenylethanol was related to Staphylococcus,Corynebacterium,and Oceanobacillus.Geranylacetone formation was closely related to Micrococcus,Oceanobacillus,and Enteractinococcus.