The biosorption and detoxification performance of Lysinibacillus fusiformis KMNTT-10 biomass for lead(II) was investigated. The optimum conditions for Pb(II) adsorption were found to be pH 6.0 and contact time 90min at 27 +/- 2 degrees C. Equilibrium data of Pb(II) adsorption fitted well with the Langmuir isotherm model and followed pseudo-second-order model. SEM-EDX analysis revealed a blister like protrusions formed on the biomass surface after Pb(II) biosorption. FTIR spectra indicated that anionic functional groups on the biomass surface took part in the adsorption process. Further, X-ray diffraction analysis showed that the adsorbed Pb(II) was transformed (detoxified) into less soluble PbS (galena).