An effective heavy metal ion adsorbent was prepared by a simple amine modification on mycelium from biomass of penicillin fermentation. The maximum adsorption capacity for Ni2+ could reach 260 mg/g after modification. The adsorbed Ni2+ could be easily desorbed by 0.01% EDTA or 0.2-0.5% HCl solution. The mechanical strength of the adsorbent was also improved after modification and the new adsorbent could be reused for at least 10 cycles without losing its uptake. The low cost adsorbent has a potential in large scale heavy metal ion wastewater treatment. (C) 2004 Published by Elsevier Inc.