Desulfosporosinus and Acididesulfobacillus dominate an acidophilic sulfate-reducing bacteria consortium during acid mine drainage bioremediation

Valdez-Nuñez L.F.; Chávez I.J.; Sekerci F.; Ayala-Muñoz D.; Straub D.; Kappler A.; Fischer S.; Mansor M. · Applied and Environmental Microbiology (2026) · DOI: 10.1128/aem.00308-26

Resumen

Acid mine drainage (AMD) is an environmental threat due to its low pH and high metal content. Biological treatment of AMD using acidophilic sulfate-reducing bacteria (aSRB) represents a potential solution for this problem, but their substrate specificity and low tolerance to extreme acidity (pH ≤3.0) and toxic metals limit their application. Here, we used an indigenous aSRB-containing consortium to remove metals and neutralize a synthetic AMD (sAMD) system starting at pH 2.9. The consortium was enriched from acidic sediments of an abandoned mine tunnel in Peru. A bioremediation experiment (pH 2.9) was set up with Fe2+ (40.25 mM), Al3+ (5.39 mM), and Zn2+ (3.97 mM) as the main dissolved metals. Glycerol and yeast extract were used as carbon sources. Physicochemical parameters, mineral formation, microbial communities, and dissolved metals were monitored for 160–200 days. At the end of the incubation, the final pH reached 6.1 and 100% of Zn2+, >99% of Fe2+, and >94% of Al3+ were removed by the aSRB consortium as X-ray diffraction-amorphous minerals. The aSRB Desulfosporosinus and Acididesulfobacillus dominated the bioremediation experiment. Two high-quality metagenome-assembled genomes taxonomically affiliated to the aforementioned aSRB showed metabolic potential related to sulfur compounds reduction as well as to organic carbon degradation (e.g., glycerol and acetate). Differences related to carbon degradation during AMD bioremediation suggest a synergy between Acididesulfobacillus and Desulfosporosinus, thus avoiding toxic waste product accumulation. Overall, we obtained a novel aSRB-containing microbial consortium that can be used for acidity neutralization and metal removal, suitable for more robust AMD treatment technologies. Copyright

Instituciones: Universidad Nacional de Cajamarca