Single and Multi‐Metal Removal by an Environmental Mixed Bacterial Isolate

This paper reports the removal of metals from aqueous solution containing Cd(II), Cr(VI), Cu(II), Ni(II) and Pb(II) by a consortia culture (CC) comprising of environmental mixed bacterial culture. The metal removal capability of growing (active) and non-growing (inactive) cell populations at initial total metal concentrations of 100 mg/l in single and multi-metal systems were examined by determining percentage metal removal and specific metal uptakes (q0). The removal and uptake performance of consortia culture in the multi-metal system was 23-58% lower compared to the single metal system (p < 0.05). The efficiency of metal removal in the single metal systems were in the order of : Pb > Cu > Ni > Cd > Cr. Growing cells displayed higher metal removal and uptake capability compared to non-growing cells for all metals tested except for Ni. For both growing and non-growing populations, the order of metal removal was Pb > Cu > Ni > Cd > Cr. TEM studies showed that metals were deposited both intracellularly and extracellularly for the two cell populations. XRF analysis confirmed the identities of the sorbed metals.