Isolation and characterization of nickel uptake by nickel resistant bacterial isolate (NiRBI).

OBJECTIVE Bioremediation technology has gained importance because microbes could be the convenient source of bio-absorption/bioaccumulation of metals from effluent streams. METHODS The nickel-resistant bacterial isolates (NiRBI) were selected from various bacterial isolates from industrial effluent and grown in nutrient broth containing different concentrations of nickel sulfate (0.3-3.0 mmol/L) and their capability of accumulating metal from the medium. RESULTS Well-defined growth of NiRBI was observed in the medium containing up to 2.5 mmol/L of nickel. The isolate was identified using 16S rRNA and closely related to Pseudomonas fragi. Maximum accumulation of nickel (0.59 mg/g dry weight of bacterial cells) was observed when NiRBI was grown in media containing 2 mmol/L of nickel. The protein profile of the NiRBI cellular extract by SDS-PAGE showed two metal stress-induced proteins of molecular weight 48 KD and 18 KD with a simultaneous down regulation of four proteins of 46.7 KD, 42.2 KD, 19.7 KD, and 4.0 KD. CONCLUSION 48 KD and 18 KD proteins play a role in metal resistance mechanism by NiRBI.