Exploring Copper-Resistant Bacterial Diversity in Coal Mines: Implications for Environmental Bioremediation
Harshit Shil, Pranjal Sharma, Rajneesh Gola
Abstract
Acid mine drainage (AMD) is a persistent consequence of coal mining, highly acidic, metal- rich enviroments that severely affect soil and water. Copper (Cu) is especially toxic and persistent, yet certain microorganisms adapt to these extreme conditions. This study investigated the diversity, resistance mechanisms, and bioremediation potential of Cu-resistant bacteria in AMD-affected soils from Raniganj, Bokaro, and Korba (India). Soils were analyzed for pH and heavy metals, showing showing acidic conditions and high contamination (Cu: 160 mg/kg; Ni: 2109 mg/kg). Bacteria were isolated and screened for copper tolerance, siderophore production, and antibiotic susceptibility. The microbial community was dominated by resilient Bacillus species (B. cereus, B. toyonensis, B. thuringiensis), along with Enterobacter, Klebsiella, and Acinetobacter, and Actinobacteria of the genus Arthrobacter. Many isolates showed remarkable copper tolerance, with minimum inhibitory concentrations (MICs) reaching up to 15 mM. adaptations included catalase activity, sporulation in Bacillus spp., and strong siderophore production in Enterobacter and Klebsiella. Antibiotic resistance profiles revealed multiple resistances, suggesting co-selection pressures in these metal-stressed environments. overall, indigenous cu-resistant microbes. Demonstrated impressive resilience and emerge as promising natural allies for sustainable remediation of AMD-contaminated sites.