Molecular characterization of cellulose-degrading Bacillus pumilus from the soil of tea garden, Darjeeling hills, India.

Bio-fuel produced from ethanol is economically and environmentally advantageous in context of changing global climate. A large number of microorganisms are capable of cellulase production but most of them cannot be utilized commercially due to their low activity. In the present study, an effiecient cellulose degrading strain of Bacillus pumilus was obtained after thorough screening for the production of extracellular cellulases. Out of a total of 144 microbes isolated from soils of Darjeeling hills of India, nineteen were found to be cellulose degrader under in vitro conditions as observed by clearing zone on CMC - agar plates. Isolate #35 had high cellulolytic activity as observed by a clearing zone of 26.83 mm diameter formed on CMC - agar plate. The isolate was characterized and identified as Bacillus pumilus. The isolate was submitted to National Agriculturally Important Microbial Culture Collection (NAIMCC), NBAIM, Mau with Accession number NAIMCC-B-01415. Transposon (Tn5) mutants of wild type isolate Bacillus pumilus NAIMCC-B-01415 were generated and screened for the absence of cellulose degradation. Of 365 B. pumilus NAIMCC-B-01415 mutants obtained, only two were unable to degrade cellulose under in vitro conditions. Inverse PCR studies with B. pumilus NAIMCC-B-01415 :: TL5, a cellulose degradation mutant of B. pumilus NAIMCC -B-01415 revealed presence of Cys B (Cystein protein regulatory) gene involved in cellulose degradation. The participation of Cys B gene in cellulase degradation is reported here.