Journal of Pure and Applied MicrobiologyVol. 9 No. 2

Occurrence of Multiple Plasmids in Metal Resistant Bacterial Population Isolated from Coal Fly Ash Contaminated Soil

Divya Patel* and P.V. Thakare

Department of Biotechnology, Sant Gadge Baba Amravati University, Amravati, Maharashtra - 444 602, India.

Received on 20 January 2015 and accepted on 01 March 2015

 

ABSTRACT

Heavy metals pollution in the environment due to coal fly ash generated from thermal power stations posses significant global problem and necessitate definitive remediation measurement. Due to its excessive use and dumping, at high concentrations, they become toxic to both human and microbes. Bacteria have evolved mechanisms to adapt in heavy metals contaminated environments and thus represent a potential source for bioremediation processes. In the present study soil samples were collected from the vicinity around selected thermal power stations of Chhattisgarh and Maharashtra state in India. Ten heavy metals, Cr, Cu, Ni, Co, Cd, Mn, Pb, Hg, Fe and Zn were tested. The statistical analysis of test samples revealed considerably high levels of Cd, Pb and Hg. A total of 49 strains were isolated from soils from different sampling locations and 19 strains were found tolerant for Cd, Pb and Hg. The maximum tolerable concentrations (MTCs) of Cd, Pb and Hg for each isolate were determined. Observed maximum MTCs were 800 ppm for Cd, 900 ppm for Pb and 900 ppm for Hg. Plasmids of sizes approx 12, 1.3 and 0.9 kb were detected in most bacterial strains with resistance to Cd, Pb and Hg.

Keywords : Heavy metals; Metal Resistant Bacteria; Plasmids; 16SrDNA; Coal fly ash.