Cellulolytic bacteria from cattle rumen with ability to hydrolyze cellulose rich biomass were explored. The study selected Paenibacillus polymyxa ND24 from 847 isolates as the most potent strain, which can efficiently produce cellulase by utilizing sugarcane bagasse, rice straw, corn starch, CMC, and avicel as a sole carbon source. On annotation of P. polymyxa ND24 genome, 116 members of glycoside hydrolase (GH) family from CAZy clusters were identified and the presence of 10 potential cellulases was validated using protein folding information. Cellulase production was further demonstrated at lab-scale 5-L bioreactor exhibiting maximum endoglucanase activity up to 0.72U/mL when cultivated in the medium containing bagasse (2% w/v) after 72h. The bagasse hydrolysate so produced was further utilized for efficient biogas production. The presence of diverse hydrolytic enzymes and formidable cellulase activity supports the use of P. polymyxa ND24 for cost-effective bioprocessing of cellulosic biomass.