产香细菌的筛选及产香特性分析

醇化烟叶作为巨大的微生物库,具有极其可观的研究和应用价值。本研究应用模拟烟叶生长环境的烟叶浸提物培养基筛选产香细菌,并分析所筛选菌株发酵烟叶的产香特性,用于研究其在烟叶醇化中提升烟叶香味的可行性,同时探究该微生物用于生产天然香料的可能性。实验结果表明:通过烟叶浸提物培养基筛选出一株细菌HD-40,该菌可发酵烟叶可产生明显奶香味;经生理生化和分子生物学鉴定,初步表明该菌属于甲基营养型芽孢杆菌;进一步,利用该菌株发酵处理烟叶,并将发酵液萃取后GC-MS检测,与未经菌株处理的发酵液对比,其所含的酯类、醛类、酸类等对香气有贡献的成分明显增加,特别是其中3-羟基-2-丁酮的比例可高达60%以上。HD-40可发酵烟叶产生明显的奶香味,其不仅在烟叶醇化方面,用于提高烟叶香气、改善烟叶吸味等,还可在制备天然香料香精方面均有着很好的应用前景。

Screening of the Aroma-producing Strain and Analysis of Its Aromaproduction Characteristics

Aging flue-cured tobacco,as a huge microbial library,has extremely considerable research and application value.Modified LB media was 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,which were based on the principle that bacteria growing naturally in mixed communities depend on signals and nutrients present within the natural habitat.Then the aroma compositions from fermentation using the isolated strain were analyzed for evaluating its feasibility for applying to the aging process,as well as to producing flavor and fragrance.The result showed that the strain,named HD-40,with distinctive aroma was found to further study.The HD-40 was identified as one of the Bacillus methylotrophicus using two methods.The aroma compositions from fermentation with the strain HD-40 were analyzed using gas chromatography-mass spectrometry(GC-MS).And compared to the fermentation without it,esters,acids and aldehydes promoted greatly,even the proportion of3-hydroxy-2-butanone was reached 60%.In our study,the fermentation of HD-40 could produce significant milk flavor.It is promising to apply to age process for improving the aroma of tobacco leaves and to prepare flavor and fragrance.