Phages released from Acidithiobacillus ferrooxidans enhance chalcopyrite bioleaching by alleviating passivation and promoting sulfur turnover

Abstract Chalcopyrite is the most abundant copper-bearing sulfide mineral, characterized by a stable crystal structure. Bioleaching of chalcopyrite is inherently slow and further constrained by surface passivation layers during prolonged bioleaching. In this study, bacteriophages released from Acidithiobacillus ferrooxidans were introduced to promote chalcopyrite bioleaching. Mineralogical characterization, microbial profiling, and functional gene analysis were employed to reveal the underlying mechanisms. One day after phage introduction, phage abundance was 9.42 × 10 5 VLPs mL −1 in the phage-treated group, 150-fold higher than in the control (6.26 × 10 3 VLPs mL −1 ). Over a 60-day leaching period, the copper leaching efficiency of the phage-treated group was 31.72%, significantly higher than that of the control (20.43%). Phage introduction alleviated surface passivation, suppressed elemental sulfur (S 0 ) and jarosite-type deposition, and increased the apparent product-layer diffusion rate constant 3.60-fold. Bacterial diversity and the relative abundance of heterotrophic bacteria were elevated. The increase in heterotrophic bacteria may alleviate the inhibitory effects of organic matter on autotrophic bioleaching microorganisms. Genes associated with the Sox system, dissimilatory sulfur metabolism, and organic sulfur transformation were significantly enriched in the phage-treated group, consistent with enhanced S 0 turnover and reduced surface accumulation. Together, these results indicate that phage introduction enhances chalcopyrite bioleaching by alleviating surface passivation and promoting sulfur turnover through coupled interfacial and microbial regulation. This study provides a novel approach for sustainable intensification of bioleaching of refractory sulfide minerals.