产香细菌的筛选及香气成分分析

Screening of the Aroma-producing Strain and Its Key Aroma Compounds Analysis

【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。

[Purpose]Aromatic 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.[Method]Modified 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. 16 S 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 chromatographymass spectrometry(GC-MS).[Result]The 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.[ Conclusion] The aroma-producing strain M-5 is of great application value for improving the aroma of tobacco leaves and producing flavors and fragrances.