A qualitative approach to nickel and lead uptake by heavy metal resistant bacteria Klebsiella sp. 10KN

Urbanization, industrialization and other human activities has introduced a number of heavy metal contaminants in the environment. Microorganisms inhabiting such sites are well efficient in developing resistance strategies against toxic heavy metal stress. The present work qualitatively describes uptake of nickel (Ni) and lead (Pb) by epiphytic root bacteria isolated from the rhizosphere of the weedy plant, Acorus calamus treated with heavy metals viz. Ni and Pb contaminated drainage water. This bacterial strain was designated as 10KN and classified as member of Klebsiella sp. on the basis of 16S rRNA gene sequence. The isolated strain showed maximum tolerable concentration (MTC) 1500 mgL-1 in Ni and 1400 mgL-1 in Pb toxicity. On the basis of residual analysis study using Microwave Plasma Atomic Emission Spectroscopy (MP-AES) it was proved that Klebsiella sp. 10KN can tolerate Ni stress upto 76.2% whereas Pb stress upto 74.4% in 48 hrs incubation time. Due to the toxicity of Ni and Pb some morphological alterations occurred which were demonstrated by Scanning Electron Microscopy and Energy-Dispersive X-ray spectroscopy (SEM–EDX), Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM) micrographs of Klebsiella sp. 10KN. The ability of heavy metal resistant bacteria Klebsiella sp. 10KN to uptake Ni and Pb could be utilized in developing feasible bioremediation processes like biosorption and bioaccumulation technologies against toxic heavy metals