Bioleaching of phosphorus and rare earth elements (REEs) from Estonian phosphorite using Aspergillus japonicus

Abstract

Phosphorite is conventionally solubilized through chemical processes, which results in high costs and environmental pollution. The phosphate rock mined to produce phosphorus is a finite resource, which makes production and supply vulnerable to risk. Around 1,1 million tonnes of phosphorus fertilizer is used in the EU yearly. As an environmentally friendlier and more cost-effective alternative, bioleaching by Aspergillus japonicus was studied for its potential to solubilize phosphorus and REEs. Results show that A. japonicus could effectively solubilize phosphorus in NBRIP medium, while REEs remain insolubilized in batch experiments. However, some REEs (Y, La, Ce, Nd) are leached in the semi-continuous culture.