Abstract
The undesirable legacies of iron mining activities lead to unintended consequences in soil subsystem with altered geomorphic system influencing ecosystem processes. The textural and elemental composition of iron mine spoil with nutrient deficiency determines the characteristic soil microbial communities by providing habitat and nutrient resources. Extremities of iron mine overburden spoil allow the existence of specific group of microbial populations especially chemolithotrophs, which reduce Fe3+ to Fe2+ thereby influencing the biogeochemistry and mineralization of organic matter. In addition, microbes influence soil functioning due to their involvement in nutrient cycling, biotransformation, formation of stable microaggregates and structural stability. Being the initial colonizers, their presence and activity is crucial for subsequent colonization of other microbial groups in iron mine spoil over time. Therefore, emphasis has been given to isolate a chemolithotrophic bacterial strain and subsequently characterized and identified by 16S rDNA sequencing. The isolated bacterium was found to be gram-negative, obligatory and facultative chemolithotroph, which exhibited maximal growth in culture medium with pH 9 at 45oC. The bacterium was observed to be alkalophilic and moderately thermophilic exhibiting higher growth rate in heterotrophic condition as compared to chemolithotrophic culture condition. Molecular phylogenetic analysis based on 16S rDNA sequence homology of the isolated bacterium revealed its close resemblance with Methylobacterium organophilum DSM 18172T (99% sequence identity), which possess heavy metal resistance genes, regulators and metal binding proteins having the ability to survive even in such adverse environmental conditions