Biological leaching of rare earth elements

The distinctive physico-chemical features of rare earth elements (REEs) have led to an increase in demand by the global market due to their multiple uses in industrial, medical and agricultural implementations. However, the scarcity of REEs and the harsh eco-unfriendly leaching processes from primary sources beside obliviousness to their recycling from secondary sources, together with the geopolitical situation, have created the need to develop a more sustainable mining strategy. Therefore, there is a growing interest in bio-hydrometallurgy, which may contribute to the scavenging of these strategic elements from low-grade resources in an environmentally friendly and economically feasible way as with copper and gold. Several prokaryotes and eukaryotes show the ability to leach REEs, however, the success in employing these microorganisms or their products in this process relays on several biotic and abiotic factors. This review focuses on the differences made by microorganisms in REEs leaching and fundamentally explains microbes-REEs interaction.