Biodegradation of penicillin V in wastewater via a cascade bacterial–fungal synergistic FBR–EBR system

Penicillin V, one of the commonly used and refractory β-lactam antibiotics, has been detected in environmental matrices. The treatment of penicillin V-containing wastewater is particularly challenging owing to its structure specificity compared with penicillin G. In this study, a dual-strain cascade biodegradation system was constructed by combining whole cells of Paracoccus sp. KDSPL-02 with Aspergillus niger , enabling the biodegradation of penicillin V in wastewater. Based on separately immobilized KDSPL-02 and A. niger cells using alginate-chitosan-biochar and alginate-PVA-biochar composite matrices respectively, a combined fixed-bed/expansion-bed bioreactor (FBR–EBR) was developed. The immobilized cells exhibited significantly enhanced stability, maintaining high catalytic activity across a broad temperature range (35-44 °C) and pH range (5-9). The system was applied to treat 5 L of penicillin V-containing wastewater. For initial penicillin V concentrations of 200 mg/L, complete disappearance of the parent antibiotic and its detectable intermediates (phenoxyacetic acid and catechol) was achieved within 36 h, as confirmed by HPLC and NMR analyses. These results demonstrate the synergistic potential of cascade biodegradation for effectively overcoming the limitations of conventional treatment methods.