[en] The leaching step of an integrated hydrometallurgical process for the selective recovery of metals from polymetallic concentrates has been investigated. The concentrate has been produced by physical treatment of Fine Shredder Residues derived from a shredding plant processing a mixed feed. Bacterially assisted leaching experiments using a copper-adapted consortium of mesophilic bacterial strains have been carried out. Various technological parameters have been studied. Under optimal conditions about 95 % extraction levels for copper and zinc have been obtained. Bacterial presence has been found beneficial in view catalysing copper dissolution.