Real acidic mine-water drainage was seeded with Acidithiobacillus ferrooxidans to catalyse the removal of iron contained therein. The addition of At. ferrooxidans increased metal precipitation kinetics and decreased the water iron content by similar to 70%. Supplementing non-sterile mine water with a bacterial growth medium accelerated metal removal by indigenous micro-organisms both at the 500 ml shake-flask and 5 l bioreactor scale.