Exploring the potential of Aspergillus terreus 2021, WLL-ISO: A dual-functional agent for heavy metal removal and self-aggregation in wastewater treatment.

• A. terreus 2021, WLL-ISO, was isolated from Cu2+-containing wastewater. • The fungus achieves complete Cu2+ removal from 10-50 mg/L solutions. • Self-spheroidization of fungal pellets occurs during heavy metal removal. • The fungus exhibits high adsorption capacity for Cu2+, Zn2+, Fe2+, and Pb2+. • EPS secretion plays a crucial role in fungal pellet formation under Cu2+ stress. This study investigates the potential of Aspergillus terreus strain 2021, WLL-ISO, isolated from Cu2+-rich wastewater, for heavy metal removal and spheroidization. Phylogenetic analysis, supported by biochemical characterization, reveals its close affiliation with A. terreus. The fungus exhibits robust growth and diverse substrate utilization. Notably, it achieves complete removal of Cu2+ from solutions (initial concentrations: 10–50 mg/L) alongside self-spheroidization. The resulting pellets display enhanced settleability and a porous structure conducive to heavy metal adsorption. Langmuir and Freundlich models confirm the fungus's high affinity and capacity for heavy metal adsorption, particularly Cu2+, Zn2+, Pb2+, and Fe2+. EPS analysis reveals significant compositional alterations under heavy metal stress, impacting pellet formation. Three-dimensional excitation-emission matrix spectrum analysis detects activation of humic acid-like organics in response to Cu2+ stress. Moreover, the fungus exhibits promising Cu2+ removal from real wastewater, highlighting its practical potential in heavy metal remediation. The self-aggregating nature of the fungus presents opportunities for the recycling of adsorbents post-heavy metal adsorption, enhancing the sustainability of the remediation process. [ABSTRACT FROM AUTHOR]