Advances and prospects in microbial degradation of per- and polyfluoroalkys substances (PFASs)

Abstract:

Per- and polyfluoroalkyl substances (PFASs) are recognized as major environmental contaminants due to their chemical stability, long-range transport potential, bioaccumulation properties, and ecotoxicity. These compounds, characterized by high dissociation energy of C−F bonds and stable helical molecular structures, demonstrate exceptional persistence in the environment, earning the designation of “forever chemicals”. Conventional physical and chemical treatment methods, including adsorption, membrane separation, and chemical reduction based on reactive species, are capable of partially removing PFASs. However, these methods face limitations related to high operational costs and complex processing requirements. Microbial defluorination has gained attention as a promising approach for PFAS remediation due to its environmental compatibility and sustainability. This paper provides a systematic overview of the biodegradation mechanisms of PFASs and other fluorinated organic compounds under both aerobic and anaerobic conditions. It details the roles of key enzyme systems, including hydrolytic dehalogenases, reductive dehalogenases, and cytochrome P450, in facilitating microbial defluorination. Additionally, the review highlights recent advancements in enhanced bioremediation strategies, such as bio-electrochemical systems, electron shuttle mediators, and the application of specialized microbial consortia. Finally, current challenges and potential future research directions in the biodegradation of PFASs are discussed.