Fungus-bacteria sequential cooperative degradation of benzo[a]pyrene: Functional complementarity and metabolic relay...

Benzo[a]pyrene (BaP) is highly recalcitrant to efficient biodegradation due to its strong hydrophobicity and low bioavailability, which significantly constrains the efficacy of conventional bioremediation technologies. In this study, a sequential fungal-bacterial consortium comprising Fusarium sp. LF-3 and Stenotrophomonas maltophilia T2-6 was established (with the fungus inoculated 7 days prior to the bacteria). The underlying degradation mechanisms were systematically elucidated through integrated transcriptomics and untargeted metabolomics. Results demonstrated that this sequential system achieved a BaP degradation rate of 51.17% (at 20 mg/L) within 14 days, significantly outperforming both individual strains and the simultaneous co-culture system. A synergistic degradation model was revealed, characterized by fungal-led primary oxidation of BaP, EPS-mediated temporary storage and transfer of metabolic intermediates, and subsequent bacterial uptake and deep mineralization. Mechanistic analysis further clarified that the efficient removal of BaP relies on the integration of the degradation process into a shared fungal-bacterial basal metabolic network, rather than the simple superposition of isolated degradation pathways. This study provides novel mechanistic insights and strategic frameworks for the robust bioremediation of complex polycyclic aromatic hydrocarbons (PAHs) contaminants.