Fungal biosorption — an alternative treatment option for heavy metal bearing wastewaters: a review

The common filamentous fungi can sorb heavy metals from aqueous solutions. The sorption of heavy metals, Cu, Zn, Cd, Pb, Fe, Ni, Ag, Th, Ra and U, by fungal biomass has been observed to varying extents. Fungal biosorption largely depends on parameters such as pH, metal ion and biomass concentration, physical or chemical pre-treatment of biomass, presence of various ligands in solution, and to a limited extent on temperature. Fungal biosorption performs well in comparison to sorption on commercial ion-exchange resins, activated carbon, and metal oxides. Limited data indicate the potential for regenerating the biomass. The cell-wall fraction of biomass plays an important role in the sorption of heavy metals. The mechanisms of biosorption are understood only to a limited extent. The potential of fungal biomass as sorbents is indicated by the available data, and more research and development of the fungal biosorption technology is recommended.