微生物在烟叶发酵过程中的作用

目的微生物在提高烟叶品质和生产天然香精香料中均具有重要的意义。本研究探究了烟叶中分离出的产香菌株的产香特性，以及菌株的应用特征。以期为该菌株的应用提供研究基础。方法应用烟叶浸提物培养基对醇化初期的烟叶表面细菌进行了分离，并通过发酵产香筛选得到1株具有明显香味的细菌M-5，采用分子生物学方法对产香菌株M-5进行了初步鉴定，并利用气相色谱—质谱(GC-MS)联用技术分析了发酵液的香气成分。结果菌株M-5被初步鉴定为蜡样芽孢杆菌(Bacillus cereus)，进一步分析菌株M-5利用烟叶发酵液的香气成分，其所产生的香气物质较多，主要有2,3-丁二醇(23.89%)、苯乙酮(9.04%)、苯乙醇(8.13%)、丁酸乙酯(6.07%)、乙酸丁酯(4.46%)和棕榈酸(2.82%)，这些物质在改善烟叶品质和香精香料中都有应用。结论M-5菌株不仅在烟叶醇化中被用于提高烟叶香气、改善烟叶吸味等，还在制备烟叶香料香精方面有着潜在的应用前景。

Effects of X-ray irradiation on the microbial growth and quality of flue-cured tobacco during aging

PurposeAromatic bacteria show considerable promise for improving the aroma of tobacco leaves and producing flavors and fragrances in an environment-friendly way. The aim of our study was to characterize the aroma-producing strain isolated from tobacco leaves, and analyze its application characteristics. And this finding offers a valuable reference for the application of this strain.MethodModified LB media were employed to isolate the aromatic bacteria on the aging flue-cured tobacco, and the modified LB media were made by adding hot water extract of the tobacco sample. And from fermentation test, an aroma-producing bacterium M-5 was selected. 16S rDNA sequence analyses were performed to identify aroma-producing strain M-5. Additionally, the aroma compositions from aroma-producing strain M-5 fermentation were analyzed by gas chromatography-mass spectrometry (GC-MS).ResultThe strain M-5 was a Bacillus cereus. A large number of aroma compositions were detected by GC-MS, and the main components included 2,3-butanediol (23.89%), acetophenone (9.04%), phenylethyl alcohol (8.13%), butanoic acid, ethyl ester (6.07%), acetic acid, butyl ester (4.46%) and n-hexadecanoic acid (2.82%). These compounds have been used in improvement of tobacco leaves and production of flavors and fragrances.ConclusionThe aroma-producing strain M-5 is of great application value for improving the aroma of tobacco leaves and producing flavors and fragrances.