Chemolithotrophic microorganisms represent a distinct category of bacteria capable of deriving energy for their metabolic processes through the oxidation of inorganic substances. This renders them highly significant for the biogeochemical cycling of iron and sulphur. Mining areas abundant in pyrite offer advantageous habitats for these organisms due to the presence of numerous reduced inorganic compounds and extreme environmental conditions, such as low pH and elevated concentrations of dissolved metals. This study focused on the isolation, screening, and characterization of chemolithotrophic bacteria obtained from pyrite mine samples sourced from the Agargaon mines in Nagpur, Maharashtra, India. In order to facilitate the proliferation of microorganisms, we employed selective acidic media specifically formulated for the cultivation of iron- and sulfur-oxidizing bacteria. A total of 43 bacterial isolates were procured and subsequently evaluated for their capacity to oxidize ferrous iron and elemental sulphur. From the isolates that underwent primary screening, those demonstrating increased chemolithotrophic activity were chosen for further examination. The morphological and biochemical analyses demonstrated the characteristic features of acidophilic chemolithotrophs. The process of molecular identification, achieved through 16S rRNA gene sequencing, revealed that the most efficient isolates exhibited close phylogenetic relationships with Aciothiobacillus ferroxidans and Acidithiobacillus ferriphilus, with sequence similarities ranging from 98% to 99%. The results of this study support the existence of metabolically active chemolithotrophic bacterial communities in pyrite mining environments, emphasizing their potential applications in biomining and environmental bioremediation initiatives.

This study investigated chemolithotrophic bacteria from pyrite mines in Nagpur, Maharashtra, India, focusing on microorganisms that derive energy by oxidizing inorganic substances and play crucial roles in iron and sulfur biogeochemical cycling. Researchers isolated 43 bacterial strains using selective acidic media and screened them for their ability to oxidize ferrous iron and elemental sulfur. The most active isolates underwent morphological, biochemical, and molecular characterization through 16S rRNA gene sequencing, revealing close phylogenetic relationships (98-99% similarity) with Acidithiobacillus ferroxidans and Acidithiobacillus ferriphilus. The findings confirm the presence of metabolically active chemolithotrophic bacterial communities in pyrite mining environments, highlighting their potential applications in biomining and environmental bioremediation processes.