Potato starch and its mixt. with acetylated starch were extruded, subjected to immobilization of microorganisms 1.5 h and used for removing Cu, Pb and Zn ions from aq. solns. for 1, 3 and 10 days. After the mentioned time within prepared samples mechanical properties and ions content were determined. The addn. of acetylated starch resulted in increasing the ion sepn. efficiency (esp. of Cu ions) but also in decreasing the mech. properties of extrudates (compression strength).