Mycoremediation of Potentially Toxic Trace Elements-a Biological Tool for Soil Cleanup: A Review

Anthropogenic and geogenic activities release potentially toxic trace elements (PTEs) that impact human health and the environment. Increasing environmental pollution stresses the need for environmentally friendly remediation technologies. Physico-chemical treatments are effective, but are costly and generate secondary pollution on- or off-site. Phytoremediation is a biological treatment that provides positive results for PTE eradication with few limitations. Mycoremediation, a type of bioremediation to use macrofungi (mushrooms) for PTE extraction from polluted sites, is the best option for soil cleanup. This review highlights the scope, mechanisms, and potentials of mycoremediation. Mushrooms produce a variety of extracellular enzymes that degrade polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides, dyes, and petroleum hydrocarbons into simpler compounds. Cadmium (Cd), lead (Pb), mercury (Hg), chromium (Cr), copper (Cu), zinc (Zn), and iron (Fe) have been effectively extracted by Phellinus badius, Amanita spissa, Lactarius piperatus, Suillus grevillei, Agaricus bisporous, Tricholoma terreum, and Fomes fomentarius, respectively. Mycoremediation is affected by environmental and genetic factors, such as pH, substrate, mycelium age, enzyme type, and ecology. The bioaccumulation factor (BAF) can make clear the effectiveness of a mushroom for the extraction of PTEs from the substrate. Higher BAF values of Cd (4.34), Pb (2.75), Cu (9), and Hg (95) have been reported for Amanita muscaria, Hypholoma fasciculare, Russula foetens, and Boletus pinophilus, respectively, demonstrating their effectiveness and suitability for mycoremediation of PTEs.