Integrative insights into benzo[a]pyrene degradation mechanisms by Aspergillus fumigatus Z5: Spectroscopic,...

High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) pose significant environmental challenges due to their complex structures and persistent toxicity, and are difficult to be degraded by bacteria. Fungi, however, possess the ability to overcome these challenges, primarily through various enzymes with broad substrate specificity, including cytochrome P450 (CYP450), laccase, manganese peroxidase, lignin peroxidase. As a result, the development of efficient fungal strains capable of degrading HMW-PAHs is essential for advancing bioremediation strategies. In this study, Aspergillus fumigatus Z5 was isolated from a contaminated site and demonstrated a remarkable ability to degrade the highly recalcitrant benzo[a]pyrene, achieving a degradation rate of 75.43 %. Transcriptomic analysis revealed significant upregulation of 34 CYP450 genes. Among these genes, CYP3A4 (gene 8840) showed strong binding affinity for benzo[a]pyrene, as confirmed by molecular docking studies, indicating its key role in the biodegradable process. Furthermore, the metabolic network analysis showed that the electron transfer required for CYP450-mediated oxidative reactions enhanced mitochondrial oxidative phosphorylation and subsequently energy metabolism in A. fumigatus Z5. This metabolic coordination likely facilitates the complete degradation of benzo[a]pyrene. Our study illuminates the fundamental roles of CYP450 from A. fumigatus Z5 in benzo[a]pyrene degradation and provides novel insight into designing and implementing enhanced bioremediation strategies.