Isolation and Characterization of Bacteria from Natural Hot Spring and Insights into the Thermophilic Cellulase Production.

A thermophilic cellulase-producing bacterium, Bacillus velezensis strain MRC 5958, from Bakra natural hot Springs, India was characterized through genome sequencing. It has a genome size of 4,467,129 bp and a GC content of 45.7%. A cellulase purified from its fermentation broth has a molecular weight of about 18 kDa. The optimum temperature and pH for carboxymethyl cellulase activity were at 55 °C and pH ~ 7.0. The enzyme is stable over a wide range of temperatures from 30 °C to 70 °C with maximum activity observed at 48 h of incubation. The strain produces cellulase on alkali-treated sugarcane bagasse, rice straw, rice husk, rice bran, and sawdust. The sugarcane bagasse exhibited the most effective carbon source for cellulase production at (85 U/ml) followed by rice bran (68 U/ml), rice husk (60 U/ml), rice straw (48 U/ml), and sawdust (39 U/ml). Therefore, this strain can be a potential thermostable cellulase-producing candidate for converting the waste biomass into biofuel and other industrial enzymes.