Abstract: In order to screen the bacteria that can more effectively degrade the cellulose components in composts, the bacterial strains with certain cellulose-decomposing ability were isolated from the soil samples using sodium carboxymethylcellulose as carbon source. Subsequently, the isolates were phenotypically identified with Gram′s staining method and were molecularly confirmed by 16s rDNA sequence analysis. Further screening test was carried out among the obtained isolates by using cellulose-Congo red medium, filter paper degradation test and cellulase activity determination test. The results showed that a total of 41 strains of cellulose-degrading bacteria were isolated from soil samples, and 6 of them exhibited better hydrolysis capacity in cellulose-Congo red medium. Among the 6 isolates, 3 strains designated as XQ-8,XQ-10 and XQ-11 had better performance in filter paper degradation test. The 16s rDNA-based identification revealed that 2 of them were Cellulomonas gilvus and the remaining one was Pseudomonas putida. The cellulase activity of these 3 strains were determined as （28.95±1.48） U/mL, （54.70±1.56） U/mL and （58.85±3.75） U/mL, respectively. In conclusion, this study obtained 3 strains of cellulose-degrading bacteria with higher cellulase activity from wetland soil, which may provide potential high-effective cellulose-degrading bacterial strains for the development of manure composting starter.

Key words: wetland soil, cellulose-degrading bacteria, isolation and screening