Isolation and Characterization of an Arsenic Resistant BacterialStrain from Changki, Nagaland

Abstract

The present study focused on isolating arsenic (As) resistant bacteria from acid mine tailings of Changki, Nagaland and evaluating their bioremediation potential. The isolation was performed using enrichment culture approach and was 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 and 125000 µg/mL, respectively. The 16S rRNA gene sequence of the strain was found to be identical to Lysinibacillus sp. The growth behaviour of the strain in the presence of selected heavy-metals (HMs) showed a prolonged lag phase, especially in As⁵⁺. Moreover, the strain appeared to be resistant to several antibiotics. SEM and EDX analyses, revealed the presence of HM ions on the outer surface of AS3 strain. 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, strain exhibits intriguing biotechnological potential for HM bioremediation.