27-21 Perfluorooctanesulfonates (PFOS) Bioremediation Coupled to Fungal Manganese Oxidation

Session: Environmental Geochemistry and Health (Posters)

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Although phased out of production in 2002, Perfluorooctanesulfonates (PFOS) have persisted in environmental systems due to their high thermal and chemical stability. The persistence and bioaccumulative tendency of PFOS are particularly problematic for human health due to their immunotoxicity and possible carcinogenicity. Previous research found PFOS concentrations of 63,000 ng/L in Ashumet Pond, Massachusetts, USA, significantly higher than the EPA Maximum Contaminant Level of 4.0 ng/L. This region also exhibits high manganese levels from groundwater contamination. Several Ascomycete manganese oxidizing fungi, which generate reactive oxygen species (ROS), were previously isolated from Ashumet Pond. These fungi facilitate aqueous Mn(II) precipitation to Mn(IV/III) oxide minerals such as birnessites, a class of phyllomanganates with highly reactive surfaces. Given recent research indicating that PFOS can be degraded by hydroxyl radicals generated through a Fenton-like reaction between hydrogen peroxide and manganese oxides, our current research investigates whether Mn oxidation via fungi can be coupled to PFOS remediation, either through ROS-induced degradation or adsorption onto the resulting Mn oxides. We explore the potential of microbial oxidation to address these two serious environmental contaminants in the region, both manganese and PFOS. We first cultured eight of the fungal Mn oxidizers previously isolated from Ashumet Pond and identified the individual fungi and fungal co-cultures most effective at Mn oxidation, as those fungi and co-cultures are likely producing the most ROS and therefore likely exhibit the highest PFOS remediation potential. We found the co-culture of Paraconiothyrium sp. AP3s5M1B1, Phoma sp. AP3s5J1a, and Pleosporales sp. AP3s5JAC2b to most rapidly remove Mn from solution. Using this ideal fungal co-culture, we then cultured these fungi in AY media containing 0, 0.63, and 63 μg/L PFOS to test concentrations analogous to those observed at Ashumet Pond. After >95% of Mn oxidation was complete, filtrates post experiment were analyzed for PFOS concentrations via liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). This work will determine whether fungi generating ROS and producing Mn oxide minerals may be capable of removing PFOS from aquatic ecosystems.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6319

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