Characterization of a novel thermophilic, cellulose-degrading bacterium Paenibacillus sp strain B39

Aims: The aims of this study were to identify and characterize the novel thermophilic, cellulose-degrading bacterium Paenibacillus sp. strain B39. Methods and Results: Strain B39 was closely related to Paenibacillus cookii in 16S rRNA gene sequence. Nonetheless, this isolate can be identified as a novel Paenibacillus sp. with respect to its physiological characteristics, biochemical reactions, and profiles of fatty acid compositions. A cellulase with both CMCase and avicelase activities was secreted from strain B39 and purified by ion-exchange chromatography. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the molecular weight of B39 cellulase was determined as 148 kDa, which was much higher than other cellulases currently reported from Paenibacillus species. The enzyme showed a maximum CMCase activity at 60 degrees C and pH 6.5. Addition of 1 mmol l(-1) of Ca2+ markedly enhanced both CMCase and avicelase activities of the enzyme. Conclusions: We have identified and characterized a novel thermophilic Paenibacillus sp. strain B39 which produced a high-molecular weight cellulase with both CMCase and avicelase activities. Significance and Impact of the Study: Based on the ability to hydrolyse CMC and avicel, the cellulase produced by Paenibacillus sp. strain B39 would have potential applications in cellulose biodegradation.