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| Analysis of Cold-adapted Cellulose-degrading Bacterial Community Structures Under Enrichment Culturing Conditions |
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Abstract There are abundant cold-adapted cellulose-degrading bacteria resources from soil in the Da Hinggan forest of Inner Mongolia. This study was aimed at analyzing the community structure of cold-adapted cellulose degrading bacteria. Cold-adapted cellulose-degrading bacteria were isolated by enrichment culture using sodium salt of caboxy methyl cellulose(CMC-Na) medium at 10 ℃. Cellulase activity was determined by 3, 5-dinitrosalicylic acid (DNS) method. The 16S rDNA genes (V3~V5 region) were amplified by using the universal primers (34lF and 907R). The PCR products were electrophoresed by denaturing gradient gel electrophoresis (DGGE). The 16S rDNA fingerprint was obtained and the bacterial community structures were analyzed. The results indicated that the relative enzyme activity increased constantly with the extension of incubation time during the process of enrichment, the 4th generation had the highest relative enzyme activity with 30.625 IU. Some bacteria died out or increased at each generation. Four DGGE profiles of microbial community structure of four generation enrichment cultures were obtained. There were five subgroups in enrichment culture, including α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Firmicutes, and Bacteroidetes, respectively. The subgroups of Firmicutes (65.5%) and β-Proteobacteria (13.8%) were the dominant bacterial floras. This study confirmed that there were abundant resources of cold-adapted cellulose-degrading bacteria in the Da Hinggan forest of Inner Mongolia. These bacteria will have a potential value of application.
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Received: 29 October 2013
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