Department Environmental Microbiology
Per- and polyfluoroalkyl substances (PFAS): interactions with proteins, pathways, and microbial communities
Fluorinated chemicals (Figure 1) are widely used in industrial and consumer products, including food packaging materials1,2. Over 20% of pharmaceuticals and 50% of agrochemicals released in the past three decades contain one or more fluorine atoms3,4. Many of these compounds, which contain -CF3- or -CF2- groups, meet the OECD definition for per- and polyfluoroalkyl substances (PFAS), though there are some exceptions5. PFAS are a significant concern due to their health risks, particularly because some bioaccumulate in agricultural plants, animals, and animal byproducts6. PFAS are also commonly referred to as ‘forever chemicals’ because of their long-lasting presence in the environment. One reason for their persistence is that few naturally occurring compounds contain fluorine, and the product of carbon-fluorine bond cleavage (fluoride) is toxic to microbes. Nevertheless, several microbial enzyme families are capable of binding and/or biotransforming fluorinated molecules7. We are leading several projects focusing on the discovery and characterization of microbial enzymes interacting with fluorinated compounds. Our team has developed a rapid, miniaturized assay (Figure 2) aimed at detecting the cleavage of carbon-fluorine bonds8. In ongoing studies, we are further developing this assay for enzyme discovery and engineering applications.
Funding
World Food System Center
ETH Research Grants
Uniscientia Foundation
Peter und Traudl Engelhorn Foundation (Postdoctoral fellowship to Silke Probst on separate, independent PFAS project)
References cited
1. Phelps, D.W., Parkinson, L.V., Boucher, J.M., Muncke, J., Geueke, B. (2024). Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies. Environ. Sci. Technol. 58, 5670–5684.
2. Geueke, B., Groh, K.J., Maffini, M.V., Martin, O.V., Boucher, J.M., Chiang, Y.-T., Gwosdz, F., Jieh, P., Kassotis, C.D., Łańska, P., Myers, J.P., Odermatt, A., Parkinson, L.V., Schreier, V.N., Srebny, V., Zimmermann, L., Scheringer, M., Muncke, J. (2023). Systematic evidence on migrating and extractable food contact chemicals: Most chemicals detected in food contact materials are not listed for use. Crit. Rev. Food Sci. Nutr.
3. Inoue, M.; Sumii, Y.; Shibata, N. Contribution of Organofluorine Compounds to Pharmaceuticals. ACS Omega (2020). https://doi.org/10.1021/acsomega.0c00830.
4. Ogawa, Y.; Tokunaga, E.; Kobayashi, O.; Hirai, K.; Shibata, N. (2020) Current Contributions of Organofluorine Compounds to the Agrochemical Industry. iScience, 23 (9), 101467.
5. Wang, Z., Buser, A.M., Cousins, I.T., Demattio, S., Drost, W., Johansson, O., Ohno, K., Patlewicz, G., Richard, A.M., Walker, G.W., White, G.S., Leinala, E. (2021). A New OECD Definition for Per- and Polyfluoroalkyl Substances. Environ. Sci. Technol. 55, 15575–15578.
6. Rudin, E., Glüge, J., & Scheringer, M. (2023). Per-and polyfluoroalkyl substances (PFASs) registered under REACH—What can we learn from the submitted data and how important will mobility be in PFASs hazard assessment? Science of the Total Environment, 877, 162618.
7. Wackett, L.P. and Robinson, S.L. (2024). A prescription for engineering PFAS biodegradation. Biochemical Journal, 481(23), pp.1757-1770.
8. Probst, S.I., Felder, F., Poltorak, V., Mewalal, R., Blaby, I., Robinson, S.L. (2024). Enzymatic carbon-fluorine bond cleavage by human gut microbes. BioRxiv doi: 10.1101/2024.07.15.601322.