Growth-Coupled Biosorption and Metabolic Regulation Enable Efficient Copper Bioremediation by Aspergillus foveolatus FX

Copper contamination poses a threat to ecosystems and human health, driving interest in sustainable microbial remediation. In this study, the copper tolerance and removal characteristics of salt lake-derived Aspergillus foveolatus FX were systematically evaluated. The strain exhibited broad pH adaptability (3–13) and moderate salt tolerance, tolerated 4 mM Cu, and removed 92% and 67% of Cu after 7 days at 2 and 3 mM Cu, respectively. Microscopic and spectroscopic analyses revealed that Cu was primarily enriched on the hyphal surface, where hydroxyl, carboxyl, and polysaccharide-associated oxygen-containing groups participated in Cu binding. Moreover, transcriptomic and metabolite analyses showed that Cu stress upregulated genes involved in Cu transport, detoxification, and antioxidant defense, while suppressing siderophore biosynthesis, indicating a shift in metal homeostasis. Importantly, under open fermentation conditions using copper mine wastewater (1.86 mM Cu), the strain removed 72% of Cu within 3 days, along with reductions in coexisting metals (Zn, Mn, Fe, Al). These results indicate that A. foveolatus FX possesses strong Cu tolerance and adaptability to complex wastewater and may serve as a potential fungal resource for the bioremediation of Cu-containing wastewater.