Isolation and examination of copper removing bacteria from activated sludge culture

Experiments were carried out to isolate metal removing bacteria from activated sludge culture and test the metal removal capability of isolated bacteria. Two concentrations of copper solution (CuCl₂) used to select the copper-tolerance level of each isolate were 0.05 mM and 2.5 mM. Experimental data showed that isolates could be obtained by using non-selective medium (NSM) in the presence of copper. The isolates were displayed on agar plates with diverse colonial morphological characteristics. A maximum uptake of 81 mg/g dry cell mass was observed at an initial copper concentration of 50 mg/l. The minimum uptake was 9 mg/g dry cell mass. Copper uptake efficiency by isolates from NSM with 0.5 mM CuCl₂ was significantly different with those from NSM with 2.5 mM CuCl₂.