Metal accumulation by fungi: Applications in environmental biotechnology

Summary Fungi can accumulate metal and radionuclide species by physico-chemical and biological mechanisms including extracellular binding by metabolites and biopolymers, binding to specific polypeptides and metabolism-dependent accumulation. Biosorptive processes appear to have the most potential for environmental biotechnology. ‘Biosorption’ consists of accumulation by predominatly metabolism-independent interactions, such as adsorptive or ion-exchange processes: the biosorptive capacity of the biomass can be manipulated by a range of physical and chemical treatments. Immobilized biomass retains biosorptive properties and possesses a number of advantages for process applications. Native or immobilized biomass can be used in fixed-bed, air-lift or fluidized bed bioreactors; biosorbed metal/radionuclide species can be removed for reclamation and the biomass regenerated by simple chemical treatments.