Microbial Characterization and Phylogenetic Analysis of a Chemolithotrophic Bacterial Strain Isolated from Acid Mine Drainage

Excessive coal mining activities disrupt the ecosystem stability and function. The overburden when exposed to air and water, it forms acid mine drainage. Being deficient in soil nutrients and pyrite (FeS2) as major contaminants with heavy metals, it harbors specific groups of microbes especially chemolithotrophs. Realizing the facts, the present study is based on the isolation and identification of the bacterium isolated from acid mine drainage. The isolated bacterium was found to be Gram negative and round shaped cocci under the microscope, the bacterium is obligately and facultatively chemolithotroph and requires an optimal temperature of 37degC for optimal growth and proliferation. The study suggested that the bacterium was observed to be acidophilic in nature. The thermal resistance of the isolated bacterium was found out to be 2hrs 60degC. Besides, its growth pattern revealed that the isolated bacterium has a tendency to shift its metabolism from chemolithotrophy to heterotrophy culture conditions. The isolated bacterium showed sensitivity as well as resistant against different antibiotics. In addition, the culture dependent approach based on PCR amplification the 16S rDNA sequence was used to identify the bacterium isolated from acid mine drainage. Molecular phylogenetic analysis based on 16S rDNA sequence homology using neighbor-joining method suggested that the isolated bacterium belongs to Pseudomonas sp. with close affiliation with other microbial populations that have the ability to thrive in such hostile environment. All sequences used in the study were obtained from the GenBank (http://www.ncbi.nlm.nih. gov).