Influence of Native Leptospirillum ferriphilum Strains on Ferric Iron and Leached Copper Recovery from Chalcopyrite to Mesophilic Temperature Under Laboratory Conditions

Bioleaching represents a sustainable and economically viable method for recovering metals from sulfide ores. This study evaluates the bioleaching potential of eight native mesophilic strains isolated from chalcopyrite ore sourced from the Toquepala mine in Peru. The strains were molecularly and phylogenetically identified as Leptospirillum ferriphilum based on 16S rRNA gene sequencing. Bioleaching process was evaluated over 648 h in triplicate flask assays at 30 °C and 120 rpm. All strains demonstrated leaching activity, achieving an average copper recovery above 30%. Notably, strains M1D and M3E demonstrated superior performance, with iron oxidation reaching approximately 50%, copper recoveries of 34.78% and 32.61%, respectively, and peak cell counts of up to 2.45 × 109 cells/mL. Specific growth rates were determined as 0.03469 h−1 for M1D and 0.03651 h−1 for M3E. A positive correlation was observed among microbial growth, iron oxidation, and copper recovery. These results confirm the potential of native mesophilic L. ferriphilum strains as efficient agents for chalcopyrite bioleaching at moderate temperatures, supporting their application in biotechnological metal recovery processes.