Biosorption of Pb(II) and Cu(II) ions from aqueous solutions has been studied in a batch system by using a bacterial strain isolated from metal polluted soil. The bacterial strain was identified as Bacillus sp. The optimum conditions of biosorption were determined by investigating the initial pH, contact. time and the initial concentrations of metal ions at constant temperature (25 degrees C). The maximum biosorption of the metal ions was observed at pH 3.0 +/-0.1 for Pb(II) and pH 5.0 +/- 0.1 for Cu(II) ions. Biosorption equilibrium times for Pb(II) and Cu(II) ions were observed in 15 and 30 min, respectively. The maximum biosorption capacities of Pb(II) and Cu(H) ions on Bacillus sp. were determined to be 92.27 +/- 1.17 mg g(-1) at 250 mg l(-1) concentration and 16.25 +/- 1.64 mg g(-1) at 200 mg l(-1) concentration, respectively. The experimental adsorption data were fitted to Langmuir isotherm model. Competition of metal ions during biosorption was investigated in binary metal solutions. The interactions between metal ions and functional groups on the cell wall surface of the biomass were confirmed by FTIR, SEM and EDAX analysis. The results indicated that bacterial isolate Bacillus sp. is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solutions. (c) 2005 Published by Elsevier B.V.