Transformation and Defluorination of Fluorotelomer Carboxylic Acids by <i>Pseudomonas</i> sp. strain 273

sp. strain 273 defluorinates FTCAs with even numbers of nonfluorinated carbons (n:2 and n:4 FTCAs), but not those with uneven numbers (n:3 and n:5 FTCAs). Growth and transformation occurred with 1:5 FTCA but defluorination of FTCAs containing <5 nonfluorinated carbons was cometabolic and required a primary carbon substrate (e.g., sebacate). Fluoride release started with the onset of growth, increased throughout the exponential growth phase, and extended into the stationary phase. Transformation of n:2 FTCAs yielded inorganic fluoride, the corresponding (n-1):3 FTCAs, perfluorocarboxylic acids (PFCAs) with one less perfluorinated carbon atom (i.e., [n-1] PFCAs), and trace amounts of shorter-chain ([n-2], [n-3]) PFCAs. The detection of 2:2 fluorotelomer unsaturated carboxylic acid, 3-OH-1:3 FTCA, 3-keto-1:3 FTCA, 1:3 FTCA, and trifluoroacetic acid, a maximum defluorination degree of ∼35.9%, and a total fluorine recovery of ∼96.8% support that 2:2 FTCA cometabolism involves β-oxidation pathway enzymes. These findings advance our understanding of bacterial FTCA transformation and defluorination, providing insights into the environmental fate of precursors.