Mining with Microbes: A Systematic Review of Bioleaching of Rare Earth Elements from Phosphate Rocks

Abstract

Rare earth elements (REEs) play a key role in advanced materials and clean energy technologies. However, traditional methods for extracting REEs are often complex, costly, and harmful to the environment. This systematic review explores the potential of using phosphate-solubilising microorganisms as a more sustainable alternative for recovering REEs, particularly from phosphate-rich minerals such as apatite found in phosphate rock. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the review investigates existing research on microbial bioleaching of REEs using a range of microorganisms, including bacteria and fungi. It also compares important factors affecting the bioleaching process, including pH, temperature, media composition, pulp density, and particle size. The findings indicate that inconsistent data and varying parameters recorded in the studies make it difficult to establish clear correlations regarding the efficiency of bioleaching of REEs. The review highlights the need for further research to clarify the specific mechanisms behind microbial bioleaching and to understand better the roles of individual microorganisms involved in the process.