RESUMEN
Aim: To isolate and identify the potential extremophilic cellulase producing strain viz., psychrophiles, halophiles, thermophiles and to compare the Cellulase activity from samples collected from different geographical regions of India. Place and Duration of Study: Bharathiar University, Department of Biotechnology, Molecular Microbiology Lab, Coimbatore, Tamilnadu, India, between January to April 2011. Methodology: Cellulase-producing extremophilic bacteria viz., psychrophiles, halophiles, and thermophiles have been isolated from soil samples. According to morphology and pigmentation, 138 distinct bacteria were isolated and screened for cellulase activity by Gram’s iodine–carboxymethylcellulose plate (CMC) assay. On the basis of the cellulase activity, six potent cellulase-producing isolates from each cluster viz., P14, P36, H6, H13, T2 and T3 were selected for 16S rRNA gene based identification. The strains were optimized for maximum cellulase activity at various temperature and pH range. Results: The phylogenetic relationship revealed that P14 and P36 psychrophilic isolates possessed maximum identity with Bacillus simplex (100%) and Arthrobactercitreus (99%), with a cellulase activity of 14.10± 1.73 and 18.27± 0.71 UmL-1 respectively. Likewise, among halophiles, H6 and H13 were identified as Bacillus subtilis and Bacillus endophyticus (99%), with a cellulase activity of 14.87 ± 0.55 and 16.83 ± 0.44 U mL-1, correspondingly. In thermophiles, T2 and T3 showed close proximity with Bacillus amyloliquefaciens and Bacillus megaterium (99%), with a cellulase activity of 21.53 ± 1.30 and 19.93 ± 0.38 U mL-1 respectively. Conclusion: In the present study, the thermophilic isolates showed promising Cellulase activity compared to psychrophiles and halophiles.