Bioremediation Mechanisms and Therapeutic Potentials of Aspergillus terreus : a Comparative Investigation of Heavy Metal-treated and Untreated Conditions

Lo, Clement Jia Wen (2026) Bioremediation Mechanisms and Therapeutic Potentials of Aspergillus terreus : a Comparative Investigation of Heavy Metal-treated and Untreated Conditions. Final Year Project (Bachelor), Tunku Abdul Rahman of Management and Technology.

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Abstract

Bioremediation offers a sustainable approach for mitigating heavy metal pollution. However, the bioremediation of heavy metals stress and the pharmacological property of its extract remain insufficiently understood. Therefore, this study investigated the Aspergillus terreus growth optimization, bioremediation mechanisms by evaluating biosorption efficiency using adsorption isotherm models, morphological changes via FESEM-EDX and FTIR, and pharmacological potential, including antioxidant, anti-inflammatory and antibacterial properties under untreated, lead- and bismuth-treated conditions. Lead-treated fungus showed reduced growth while bismuth-treated fungus showed twofold increase in biomass at pH 4 and 35°C. Meanwhile, Langmuir showed a maximum lead uptake of 2.581 mg/g, Freundlich indicated favourable applicability, Temkin suggested endothermic with strong binding affinity, and Dubinin-Radushkevich confirmed chemisorption. The FESEM-EDX results indicated the presence of conidial and rougher surface and the FTIR demonstrated negative charged group acts as binding sites for heavy metals. The biomass grown under optimal condition was subjected to extraction by ethyl acetate and bioassays, including DPPH, FRAP, 15-LOX inhibitory and antibacterial activities via disc diffusion assay. Bismuth-treated crude extracts exhibited excellent antioxidant power (EC50 = 2.33 ± 0.33 μg/ml and 30.09 ± 1.97 mmol Fe2+/g extracts) with good anti-inflammatory properties (IC50 = 36.8964 ± 1.5957 μg/ml) while lead-treated extract showed weaker antioxidant (EC50 = 20.990 ± 3.43 μg/ml and 38.42 ± 1.32 mmol Fe2+/g extracts) and anti-inflammatory properties (EC50 value of 147.0912 ± 1.5957 μg/ml). However, all crude extracts showed no inhibition against S. aureus, K. pneumoniae, B. cereus and A. baumannii. The findings conclude that A. terreus possesses notable tolerance to heavy metal stress, with significant bioremediation potential and the ability to produce novel bioactive metabolites under stress conditions. This study highlights the dual function of A. terreus in environmental remediation and drug discovery.