Mycoremediation of heavy metal/metalloid-contaminated soil: current understanding and future prospects

In natural environments, heavy metals and metalloids are widely dispersed as a consequence of anthropogenic (e.g. mining) and geological (e.g. volcanic eruption) activities. The toxicity of these metals/metalloids could adversely affect the ecosystem as well as causing major human health concerns. Mycoremediation (remediation by fungi) has received attention from many researchers as an alternative to conventional chemical and physical methods in removing toxic metals and metalloids. A number of regulatory mechanisms to control the concentrations and counteract the toxicity of these pollutants have been observed in fungi. These mechanisms include: (i) precipitation or binding to cell surface materials, (ii) intracellular chelation and precipitation, (iii) biotransformation and (iv) control of membrane transport systems. This chapter examines the use of fungi to bioremediate metals and metalloids and their detoxification mechanisms, with special focus on an extremophilic fungus, Acidomyces acidophilus, isolated from a disused tin mine in the UK, to illustrate some of the mechanisms involved. Future biotechnological and nanotechnological prospects of metal/metalloids bioremediation using fungi are also discussed.