Microalgal screening for heavy metal tolerance and acid mine drainage bioremediation

Acid mine drainage (AMD) and heavy metal contamination pose serious environmental problems that require effective, long-term remediation technique [1, 2]. The resistance and tolerance of four freshwater microalgal strains for bioremediation were evaluated (Chlorella vulgaris, Tetradesmus obliquus, Chlorella sorokiniana, Parachlorella kesslerii). To identify strain-specific resistance, small-scale toxicity tests were initially conducted to calculate EC50 values for individual heavy metals (Table 1). Further screening was conducted under conditions of co-exposure to mixed metals, evaluating the combined effects on microalgal growth to replicate realistic polluted environments. Simultaneously, the most robust strains were grown in dilute AMD, monitoring growth performance and determining EC50 values. Then selected microalgal strains were cultured at higher volumes (70 ml) to validate their ability to remain stable during growth (Fig. 1). This multistep approach allowed us to characterize the bioremediation tolerance and limits of microalgae strains when exposed to real AMD effluents. Understanding these limits is a crucial step in translating laboratory-scale bioremediation research into practical, real-world applications. Overall, this study contributes to the broader development of sustainable and scalable biotechnological solutions for water remediation.