Biodegradation of per- and polyfluoroalkyl substances (PFAS): A review

Per- and polyfluoroalkyl substances (PFAS) are a group of chemicals widely manufactured for industrial and commercial applications in the past decades due to their remarkable stability as well as hydrophobic and lipophobic nature. PFAS species have been recognized as emerging environmental contaminants of concern due to their toxicity and environmental persistence, thereby attracting intensive research seeking effective technologies for their removal from the environment. The objective of this review is to provide a thorough analysis of the biodegradation of PFAS in multiple environmental matrices and offer a future outlook. By discussing targeted PFAS species, degradation intermediates, degradation efficiencies, and microbial species, a comprehensive summary of the known microbial species and their degradation pathways are presented. The biodegradation pathways for different types of PFAS species are summarized in two major categories, biodegradation with and without the cleavage of C-F bond. Existing uncertainties and future research directions for PFAS biodegradation are provided.