The protonated biomass of Corynebacterium glutamicum was used for the removal of Reactive Black 5 (RB 5). In batch experiments, the parameters studied included the effect of the dye concentration, pH, contact time, salt concentration and temperature. In the range of pH 1-3, the removal of RB 5 was kept at near 100%. The maximum uptakes estimated by using the Langrnuir model were 169.5 and 185.2 mg/g at 20 and 40 degrees C, respectively. Kinetic studies showed a pseudo second-order rate of biosorption with respect to the solution. The uptake of RB 5 was not significantly affected by the high concentration of salts. Various thermodynamic parameters such as AG degrees, AH degrees, and AS degrees were evaluated with results indicating that this system was a spontaneous and endothermic process. In addition, the biomass could be repeatedly reused up to five times of sorption/desorption cycle, confirming that the biomass wastes can be a potential regenerable biosorbent for RB 5 removal. (c) 2006 Elsevier B.V. All rights reserved.