Abstract：Finding suitable cellulose degrading bacteria is the key to the effective application of cellulose in Inner Mongolia and other northern regions. In order to obtain some efficient cellulose-degrading bacteria, traditional isolation and enrichment culture technologies were used to isolate cellulose-degrading bacteria from the soil in western region of Inner Mongolia, and the degradation characteristics of cellulose-degradation bacteria were analyzed. A preliminary identification was based on analyzing the similarities of 16S rDNA gene sequences of the isolates. Cellulase activity was determined by DNS (3,5-dinitrosalicylic acid) method. And the enzyme-producing conditions of the highest enzyme activity cellulase-producing strain was further optimized. The results showed that a total of 59 cellulolytic bacteria were isolated, including 36 cold-adapted cellulose-degrading bacteria isolated at 10 ℃ and 23 cellulose-degrading bacteria isolated at 28 ℃. The 16S rDNA gene sequences indicated that these strains belonged to Alpha-Proteobacteria, Gamma-Proteobacteria, beta-Proteobacteria, Bacteroidetes, and Actinobacteria, respectively. Alpha-Proteobacteria was the first dominant group of room temperature cellulose-degrading bacteria, beta-Proteobacteria and Actinobacteria were the second dominant group. Gamma-Proteobacteria was the first dominant group of cold-adapted cellulose-degrading bacteria, Bacteroidetes was the second dominant group. At the genus level, Pseudochrobactrum was the first dominant genus of room temperature cellulose-degrading, while Pseudomonas was the second dominant genus, and Pseudomonas was the first dominant genus of cold-adapted cellulose degrading bacteria at low temperature, while Sphingobacterium was the second dominant genus. Among these strains, strain CB04 (belonging to Cellulomonas) had the highest carboxymethyl cellulose (CMC) activity. After optimization, the optimal conditions for enzyme production were as follows: the yeast extract was nitrogen source, the culture time was 4 d, the pH value was 7, and the CMC enzyme activity was up to 114.6 U/mL. The strain CB04 was a cellulase producing bacterium with great development potential. This study preliminarily revealed the composition and ability of cellulose-degradation bacteria in western region of Inner Mongolia, which provides a theoretical and practical basis for understanding and using cellulose-degradation bacteria for other applications.
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