Extracellular compounds produced by bacterial consortium promoting elements mobilization from polymetallic Kupferschiefer black shale (Fore-Sudetic Monocline, Poland)

•The extracellular compounds produce by bacterial consortium.•Complexation of selected elements (As, Co, Mn, Mo, Fe, Ni, V).•Elements redistribution from sedimentary rock.

Culture experiments employing Fe-deficient medium showed that a consortium of indigenous microorganisms isolated from Kupferschiefer black shale produced a mixture of extracellular compounds containing siderophores which could form complexes with a wide range of elements and were able to mediate element mobilization from polymetallic black shale. The mobilization of a diverse array of elements including a number of essential trace elements (Co, Cu, Mn, Mo, Zn) and toxic species (As) was shown. Since the bacteria used in this study were originally obtained from a subsurface copper deposit, these results highlight the potential importance of extracellular compounds in biogeochemical cycles of elements in underground environment and their ecological significance in promoting the uptake of essential trace metals and resistance to toxic elements.