Synergistic Degradation of Acetaminophen by a Bacterial-Fungal System and its Mechanism

Abstract

Microbial degradation of acetaminophen (APAP) is an effective bioremediation strategy. In this study, a bacterial-fungal system was constructed using the APAP-degrading bacterium Pseudomonas sp. A8 and the 4-aminophenol (4-AP)-degrading fungus Cladosporium sp. APM-1, which achieved complete degradation of 500 mg/L APAP. Compared with the pure A8, the bacterial-fungal system increased the APAP mineralization rate from 72.64% to 88.42%. The concentration of 4-AP, a toxic intermediate product of the APAP biodegradation, was significantly reduced. Genome analysis revealed that A8 had annotated genes relevant for APAP degradation (amidase and hydroxylase), while more genes related to the degradation of 4-AP and downstream metabolites (deaminase, dioxygenase, monooxygenase, and laccase) were annotated in APM-1. In the bacterial-fungal system, synergistic effects led to a more complete mineralization of APAP. Furthermore, analysis of the degradation products of the different systems showed that the adding APM-1 provided an additional degradation pathway (catechol pathway), contributing to APAP mineralization as well. Overall, this study proposed a novel bioremediation strategy for APAP and provided a theoretical basis for its biodegradation mechanism.

Keywords: Acetaminophen, Biodegradation, Genomics, Degradation products