Role of bacteria and mycorrhizal fungi in phytomining: status and future perspectives

The ever-growing demand for metals has been fueling the development of alternative technologies to recover elements of interest from subeconomic deposits. One such example is phytomining, a technique that employs plants with the ability to accumulate astonishing amounts of metals in their tissues. These plants, called hyperaccumulators, can be used to retrieve metals such as Ni or Au from ultramafic soils and mine tailings, respectively. The rhizosphere of hyperaccumulators is often populated by large amounts of microorganisms mainly consisting of bacteria and mycorrhizal fungi. These microorganisms can enhance plant biomass production, reduce metal phytotoxicity, and increase the bioavailability of certain elements of interest. In this chapter, we review the role of bacteria and mycorrhizal fungi in phytomining and outline future perspectives of their application to enhance this green metal-recovery technique.