Isolation and Characterization of Moderate Thermophilic Bacteria

The present work is the first report of moderate thermophilic bacteria from the coastal waters of Coramandal coast, Chennai, Tamilnadu. Of the 334 bacterial isolates, only 44 isolates were found to grow up to 55°C. The isolates showed highest incidence of antibiotic resistance to most of the antibiotics tested. Polyphasic approach viz., biochemical tests, Fatty Acid Methyl Ester Analysis (FAME), SDS-PAGE analysis, 16S ribosomal RNA gene analysis and Scanning Electron Microscopy (SEM) was adopted to identify the moderately thermophilic bacterial isolates. Biochemical tests indicated the isolates were Bacillus spp. FAME analysis showed that the predominant fatty acid was 15:0 iso and 15:0 anteiso which is a characteristic feature of Bacillus spp. Protein bands of 40-44 kDa were over-expressed when isolates were grown at 50ºC. The results of BLAST clearly showed that the 16S rRNA gene sequences of the ten Gram-positive moderately thermophilic bacterial isolates were similar to the sequences of Bacillus spp. SEM analysis showed that the isolates were long and short slender bacilli.