Enzymatic Transformation and Degradation of Poly- and Perfluoroalkyl Substance (PFAS): Understanding the Toughest Problem of Soil Organisms

Abstract

Poly- or perfluorinated organic substances, collectively termed PFAS, are chemicals that contain at least one fully fluorinated carbon atom group. Owing to the strength of the C–F bond and peculiar physical and chemical properties, PFAS are highly persistent and mobile in the environment, and bioaccumulative. In this paper we evaluate the main factors hampering the enzymatic transformation and degradation of PFAS in soil, their potential impact on soil enzyme activity, and discuss possible approaches for evaluating PFAS enzymatic transformation and degradation in soil. We summarise the latest hypotheses and findings on enzymatic defluorination mechanisms, which could explain some PFAS degradation patterns observed in in vitro studies and in soils from contaminated areas, and compare them with the known enzyme catalytic kinetics. We also illustrate the approaches which could be used to analyse the PFAS transformative and biodegradative potential of soil microbial communities, stemming from theoretical considerations and evidence from in silico simulations and laboratory approaches currently used to evaluate PFAS transformation and biodegradation. We also highlight the importance of merging complementary skills and innovative approaches to develop new scientific approaches.