Mechanisms of lead uptake by fungal biomass isolated from heavy metals habitats

As a part of a broader study aimed at developing a biosystem for wastewater treatment, Penicillium sp., isolated from a heavy metals contaminated soil in Tangier (Morocco), wasused to assess the biosorption of Pb2+ ions onto both dead and alive cells. The cellular location of the accumulated lead was investigated by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX), allowing asorption mechanism to be proposed. Moreover, the maximum absorption capacity of lead ions was determined for several initial pH and Pb2+ concentrations following Langmuir, Freundlich and Langmuir-Freundlich isotherm models. The biosorption capacity of Penicillium sp. showed a pH-dependent profile; maximum adsorption capacity (q max) of Pb2+ ontowet and dry Penicillium sp. biomass was 60.76 and 52.09mg g-1, respectively, at 5.5 initial pH, the process being more accurately described by the Langmuir-Freundlich model. Cell bounding places of lead ions were evidenced and the adsorption capacity of Penicillium sp. was calculated. These results support the potential utility of this microorganism for lead removal from contaminated water.