Cometabolic and nutrient-driven defluorination and transformation of per- and polyfluoroalkyl substances by...

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants of great concern. Yet, current knowledge of PFAS-degrading microorganisms is limited. Here, we report novel bacterial strains, Cupriavidus sp. CuC1, Pseudomonas sp. PsB, and Variovorax sp. VaC1, capable of defluorinating diverse C1-C6 fluorinated PFAS and using nitrogen (N)- and sulfur (S)-containing PFAS as nutrients. These bacteria exhibited broad metabolic versatility toward various sugar, carboxylates, alcohols, alkanes, aromatic, hydrocarbon surfactants, and organic solvents. In particular, 1-butanol (BuOH)-grown CuC1 effectively defluorinated C1-C6 fluorinated PFAS. Strain PsB significantly removed 6:2 fluorotelomer sulfonamidoalkyl betaine (FtSaB) and N-ethyl perfluorooctane sulfonamide as sole N-sources. All three strains removed 6:2 fluorotelomer sulfonate (FtS) as a sole S-source and accumulated various PFAS (suspect) metabolites when grown from selective carbon source types. Strains CuC1 (ethylene glycol-, BuOH-, or octanoate-grown) and VaC1 (glucose-grown) achieved > 95% 6:2 FtS removal. Strain VaC1 uniquely accumulated a novel metabolite, α-OH 6:2 FtS, that corresponded with higher accumulation of 6:2 fluorotelomer unsaturated carboxylic acid. Furthermore, CuC1 demonstrated 6:2 FtS removal when grown on sodium octyl sulfate under S-rich conditions and showed potential removal in 6:2 FtSaB and undecafluoro-2-methyl-3-oxahexanoic acid (commercial name GenX) under S-limited conditions. These findings significantly expand the portfolio of PFAS degraders and provide new mechanistic insights into nutrient-driven PFAS biotransformation.