Isolation and Characterization of an Arsenic-Resistant Bacterial Strain from Changki, Nagaland

The present study focused on isolating arsenic (As)-resistant bacterium from acid mine tailings of Changki, Nagaland, and evaluating its bioremediation potential. Isolation was performed using an enrichment culture approach and further characterized using standard procedures. The obtained bacterial strain AS3 was found to be resistant to As3+ and As5+ ions up to 1562 μg.mL-1 and 125000 μg.mL-1, respectively. The 16S rRNA gene sequence of the strain was found to be identical to that of Lysinibacillus sp. The growth behavior of the strain in the presence of selected heavy metals (HMs) showed a prolonged lag phase, especially in As5+. Moreover, the strain was found to be resistant to several antibiotics. SEM and EDX analyses revealed the presence of HM ions on the outer surface of the AS3 strain. The available functional groups on the surface of the AS3 strain cells engaged in the metal-binding process were identified using FTIR, suggesting their active participation in adsorption. AAS showed that the strain had the potential to remove As3+ and As5+ ions with removal efficiencies of 99.94% and 99.49%, respectively. Based on the findings, the strain exhibits intriguing biotechnological potential for HM bioremediation.