Dynamics Of Bacterial Community Composition On The Aging-flued Tobacco Leaves And Isolation Of A Bacterial Community With Cellulose-degrading Ability From Aging Flue-cured Tobacco Leaves

Bacterial composition on the surface of the aging flue-cured tobacco leaves was investigated using PCR-DGGE technology. The tobacco leaves of8grades, including Yunnan Wenshan C/S,Yunnan Wenshan B22,Yunnan Wenshan X21,Henan C/S, Henan B22, Fujian C/S, Fujian B22and Fujian X21, were sampled from Shanghai Tobacco Group Co., Ltd. With the aim to study the effect of high temperature, the place of tobacco production, the tobacco grade and the aging time on the bacterial compostion on the tobacco leaves during aging, the bacterial compostion on the surface of tobacco leaves were analyzed during aging and summer. Our results indicated that no regular change of the bacterial community compostion on the surface of the tobacco leave samples was found.A bacterial community with the ability to degrade cellulose was isolated from aging flue-cured tobacco leaves for the first time. The analysis of16S rDNA PCR-DGGE suggested that the bacterial community was mainly consisted of five species. After inoculation, the bacterial community reached the log phase quickly, and reached the peak of OD6oonm at3rd day. The pH value raised gradually after inoculation of the bacterial community, and reached the maximum value at the8th day. At20℃, the cellulase activity of the bacterial community was very low. With the temperature increasing, the cellulose activity increased, and reached the peak at60℃. When the temperature exceeded60℃, the cellulose activity decreased dramatically. With the pH value inceasing from3to8, the cellulose activity increased gradually, and reached the peak at pH8. When the pH value increased from8to9, the cellulose activity dropped sharply. The bacterial community was able to degrade the cellulose in the tobacco leaves, filter paper and the tobacco stalk. The cellulase activity of the bacterial community fermented in the tobacco leaves was significantly higher than that in the filter paper and tobacco stalk.The result of the experiment shows that the bacteria could have influence on the cellulose of tobacco leaves and affect the character of the tobacco during aging. The bacterial community could be used to degrade the cellulose of tobacco leaves and tobacco stalk in order to improve the quality of the tobacco leaves and stalk.