Effective bioremoval of Cu (II) and Sulfate from acid mine drainage via biomineralization with an extreme acidophile bacterium V. pantothenticus WL

The management of acid mine drainage (AMD), characterized by high acidity and toxic heavy metals, remains a persistent and costly global environmental challenge. Conventional active treatments are chemical-intensive and economically unsustainable, while passive biological systems often lack resilience under extreme conditions. Here we show a novel bio-strategy for effective AMD management using an extreme acidophilic bacterium, Virgibacillus pantothenticus WL, isolated directly from AMD. This strain demonstrated exceptional inherent tolerance, thriving at pH 3.0 and Cu(II) concentrations up to 200 mg/L. V. pantothenticus WL achieved high Cu(II) removal efficiencies of 85 % and 80 % from 100 mg/L and 200 mg/L Cu(II) solutions through a self-sustaining process. The removal was mediated by a synergistic mechanism where bacterial sulfate reduction precipitated Cu(II) as stable sulfide minerals (chalcocite and covellite), while concurrent metabolic activity elevated the system pH, activating the metal-binding capacity of extracellular polymeric substances for enhanced biosorption. This integrated microbial process simultaneously addresses multiple AMD pollutants-neutralizing acidity, removing sulfate, and immobilizing heavy metals-without continuous chemical inputs. The findings demonstrate a nature-based solution that can be integrated into treatment systems, offering a sustainable and manageable alternative for long-term AMD remediation. This study provides a critical foundation for advancing the practical application of specialized microbes in environmental managements.