Assessment of heavy metal tolerance and biosorptive potential of Klebsiella variicola isolated from industrial effluents

Heavy metal contamination now a day is one of the major global environmental concerns. Textile effluents of Faisalabad Pakistan are heavily contaminated with heavy metals and demands to explore native microorganisms as effective bioremediation tool. Study aimed to isolate heavy metal tolerant bacteria from textile effluents of Faisalabad Pakistan and to evaluate their biosorptive potential. Out of 30 collected samples 13 isolates having metal tolerance potential against Ni and Co were screened out. Maximum tolerable concentration and multi metal resistance was determined. A native bacterial strain showing maximum tolerance to Ni and Co and multi metal resistance against Ni, Co and Cr at different levels was selected and named as Abuzar Microbiology 1 (AMIC1). Molecular characterization confirmed it as Klebsiella variicola which was submitted in First fungal culture bank of Pakistan (FCBP-WB-0688). ICP-OES revealed that it reduced Ni (50, 49%) and Co (71, 68.6%) after 24 and 48 h, respectively. FT-IR was used to analyze functional groups and overall nature of chemical bonds. Changes in spectra of biomass were observed after absorption of Ni and Co by K. variicola. SEM revealed morphological changes in bacteria in response to metal stress. Both metals affected bacterial cell wall and created pores in it. However effect of Ni was more pronounced than Co. It was concluded that K. variicola, a native novel strain possessed significant heavy metal tolerance and bioremediation potential against Ni and Co. It may be used in future for development of bioremediation agents to detoxify textile effluents at industrial surroundings.