Removal of perfluoroalkyl acids in industrial waste-landfill leachates by bacteria isolated from river sediments polluted with perfluoroalkyl acids

Seven bacterial strains isolated from river sediments contaminated with per- and polyfluoroalkyl substances (PFAS) were evaluated for their ability to remove perfluoroalkyl acids (PFAAs) present in a culture media and industrial waste-landfill leachates. The isolates belong to the genera Rhodococcus , Priestia , Paenibacillus , and Xanthobacter . Under optimal growth conditions, Xanthobacter autotrophicus (XaP) and Priestia flexa (PfR) significantly (up to 17.8%) decreased perfluorooctanesulfonic acid (PFOS) concentrations, while Priestia megaterium (PmB) decreased perfluorooctanoic acid (PFOA) by 14.1%. Both linear (L-PFOS) and branched (B-PFOS) isomers decreased during incubation, although L-PFOS decreased to a greater extent. PFOS, which has a higher hydrophobicity than PFOA, were more strongly adsorbed onto bacterial cells than PFOA. The two Gram-negative bacterial strains showed higher adsorption of PFOS and PFOA than the Gram-positive bacterial strains. XaP caused the greatest removal in PFOS, and time-course analysis indicated that adsorption likely occurred via extracellular polymeric substances. Experiments involving leachate treatment showed that XaP contributed to PFAA removal, demonstrating its applicability beyond laboratory culture conditions. These findings demonstrate that indigenous bacterial strains exhibit distinct PFAS removal behaviors depending on PFAS structure and isomer type, with adsorption playing one of major roles in the removal process. Our results provide new insights into strain-specific PFAS interactions and suggest that selected indigenous bacteria could be useful for the bioremediation of PFAS-contaminated environments.