Mechanistic insights into the enhancement of MgSO4-mediated leaching of ion-adsorption rare earth ores by Penicillium sp. fermentation broth

The fragility of the global rare earth supply chain and the urgent demand for sustainable exploitation have driven intensive research into green and high-efficiency extraction technologies. Bioleaching technology, distinguished by its environmental compatibility and resource adaptability, has emerged as a transformative alternative to conventional chemical leaching methods. This study focuses on the multiphase utilization of ion-adsorption rare earth ores by leveraging Penicillium sp. fermentation broth to promote MgSO 4 -mediated leaching through a biologically enhanced chemical process. The objectives were to elucidate the rare earth leaching mechanisms under bio-promoted chemical processes and to optimize strain cultivation and leaching parameters. Untargeted metabolomics was applied to delineate dynamic changes in differential metabolites before and after leaching, while Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were utilized to clarify metabolite-mineral interfacial interactions. The results demonstrated that the composite system achieved a rare earth recovery rate of 93.79 % under optimal conditions (liquid-to-solid ratio of 4:1, 6-hour leaching), significantly outperforming conventional chemical leaching. Metabolomic analysis revealed a multifunctional interaction network involving organic acid-mediated proton attack, lipid molecule-driven interfacial modification, and benzenoid compound-regulated redox balance. This study demonstrates that the fermentation broth of Penicillium sp. significantly enhances MgSO 4 -mediated leaching efficiency of ion-adsorption rare earth ores, thereby offering a sustainable pathway to address resource and environmental challenges in rare earth industries.