The ability of Streptomyces rimosus biomass to bind zinc ions in batch mode was shown recently. The aim of this study was to determine the zinc uptake capacity by Streptomyces rimosus biomass in continuous mode. Bacterial biomass was able to bind more Zn(II) after pretreatment with sodium hydroxide (1 mol dm(-3)) than without treatment. The maximum adsorption capacity and the adsorption capacity at the saturation point calculated by means of both the exchange zone model and the Thomas model were practically identical of about 2.9 mg(Zn(II)) g(-1) (biomass). This result was lower than the batch adsorption capacity of Streptomyces rimosus, indicating that the packed-bed is not the most appropriate process to exploit the bacterial biomass adsorption capacity, The effect of zinc concentration in the range of 10 to 200 mg(Zn(II)) dm(-3) on the biosorption capacity of the packed-bed was not significant. Biomass regeneration with 0.1 mol dm(-3) HCl gave a 90% recovery of the adsorbed Zn(II),