Evaluation of the heavy metals tolerant UV rays treated bacteria isolated from anthropogenic sites of Chambal region, India

Abstract

Industrial waste is released into the environment and leads to various types of heavy metal, which are toxic, mutagenic and carcinogenic in nature. Heavy metals are not biodegradable but accumulated by living organisms and cause diseases at even low concentrations. In this study, we selected four anthropogenic sites from Chambal region, isolated bacteria and investigated its heavy metal removal capability. The bacteria was isolated and identified as Escherichia coli (Ag-5), on the basis of biochemical and 16S rRNA gene sequence. Among the five (cadmium, cobalt, lead, nickel and zinc) heavy metals studied, Ni2+ has been observed to be highly toxic with minimum inhibitory concentration score of 200 ppm. E. coli could tolerate Zn2+ (300 ppm), Cd2+ (400 ppm), Co2+ (400 ppm) and Pb+2 (500 ppm). Heavy metal tolerance capability was also evaluated by UV rays treated E. coli (Ag-5) isolate and compared with wild strain Ag-5. The result indicated that the tolerance capability was enhanced by UV rays treated bacterial isolate as compared to wild strain with respect to all tested heavy metals. Atomic absorption spectroscopy results revealed that wild strain removed 78.2% cadmium nitrate, while UV rays 30 and 60 s. exposed strain removed 85.9 and 83% cadmium nitrate. Wild strain removed 64.4% nickel chloride, while UV rays 30 and 60 s exposed strain removed 66.9 and 74.5% nickel chloride. The results indicate that indigenous E. coli treated with UV rays could serve as heavy metal tolerant bacteria and utilized in bioremediation processes.