This study assesses the ability of mycelia of Aspergillus niger B-77 (both free and immobilized on polyurethane foam) to remove copper from single-ion solution. All experiments were conducted using 0.5 mM solutions of CuSO4. 5H(2)O. Mycelia immobilized on polyurethane foam cells showed a three-fold increase in uptake, compared with that of free cells. The efficiency of copper removal (mg Cu2+ removed/mg Cu2+ added) in a column system reached more than 99% before the break-through point was attained.