陈化烟叶中纤维素降解菌群的分离及其特性研究

从陈化烟叶中分离到具有降解纤维素活性的菌群，分析了温度、pH和纤维素材料对菌群酶活性的影响，采用16SrDNA片段的PCR-DGGE（变形梯度凝胶电泳）技术分析菌群组成。结果显示，菌群主要由5种细菌组成。20℃时菌群纤维素酶活性很低，随着温度升高酶活性升高，在60℃时纤维素酶活性达到最高值，继续升温则酶活性下降。pH从3升高到8时，菌群纤维素酶活性不断增大，pH为8时酶活性达到最大，pH继续升高到9时则酶活性下降。菌群对烟叶、滤纸和烟梗中的纤维素都有降解作用，在以烟叶作为纤维素材料培养菌群时，纤维素酶活性明显高于滤纸和烟梗。陈化过程中微生物可能对烟叶纤维素有降解作用，从而影响烟叶的陈化效果；可以利用分离到的菌群在烟叶或烟梗发酵中降解纤维素，改善烟叶或烟梗的品质。

Isolation and Characterization of Bacterial Community with Cellulose-Decomposition Ability from Aging Flue-cured Tobacco Leaves

Large amounts of bacteria have been found on aging flue-cured tobacco leaves. A bacterial community with the ability to decompose cellulose was isolated from aging flue-cured tobacco leaves. The effects of temperature, pH value and different cellulose source on the cellulase activity of bacterial community were further investigated. 16S rDNA PCR-DGGE technology was used to analyze bacterial community composition. The results showed that the bacterial community mainly consisted of five species. At 20℃, the cellulase activity of the bacterial community was very low. With the temperature increasing, the cellulase activity increased, and reached the peak at 60 ℃. When the temperature exceeded 60 ℃, the ceUulase activity then decreased dramatically. With the pH value increasing from 3 to 8, the cellulase activity increased gradually, and reached the peak at pH 8. When the pH value increased from 8 to 9, the cellulose activity dropped sharply. The bacterial community was able to decompose 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. In conclusion, the bacteria may have influence on the cellulose decomposition of tobacco leaves and affect the character of the tobacco during aging. The bacterial community may be used to decompose the cellulose of tobacco leaves and tobacco stalk in order to improve the quality of the tobacco leaves and stalk.