Bioleaching of lepidolite by Sulfobacillus thermosulfidooxidans with different energy substrates

This study investigated the impact of energy substrate selection on the bioleaching mechanism of lepidolite by the dominant bioleaching bacterium Sulfobacillus thermosulfidooxidans . Through the establishment of bioleaching systems driven by distinct energy substrates (S 0 , Fe 2+ , and FeS 2 ), we demonstrate that the process is coregulated by multiple factors: acidification via H⁺ dissolution, metal ion adsorption by extracellular polymeric substances (EPS), and dual promoting and inhibitory effects arising from secondary mineral formation in FeS 2 /Fe 2+ systems. Overall, proton-driven acidification is likely the decisive factor governing leaching efficiency. Metabolomic analysis revealed significant substrate-induced metabolic variations, with critical regulation observed in the nicotinate/nicotinamide metabolism, pantothenate/CoA biosynthesis, and carbon-nitrogen metabolic pathways. These adaptations crucially regulate electron transfer, iron/sulfur oxidation, and mineral phase stability, ultimately determining differential leaching performance. This work elucidates the pivotal role of energy substrate selection in lepidolite bioleaching efficiency, providing theoretical guidance for high-efficiency strain screening, leaching process optimization, and recovery rate enhancement. • Energy substrates are key determinants of lepidolite bioleaching efficiency. • Bioleaching involves acid dissolution, EPS adsorption and secondary mineral formation. • Substrates affect metabolic shifts regulating electron transfer and Fe/S oxidation.