CAS-SC: Mechanistic Understanding of Biodechlorination-facilitated Defluorination of Polychlorofluoroalkyl Substances

Polychlorofluoroalkyl substances (PCFAS) represent a large sub-class of emerging per- and polyfluoroalkyl substances (PFAS) widely used and detected in the environment. However, there is limited understanding of their fate and transport in the environment, molecular transformation, and mitigation strategies. With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Yujie Men and Jinyong Liu at the University of California, Riverside, and their students will study the molecular mechanisms of dechlorination-facilitated defluorination processes in biological and chemical systems. This project will train graduate, undergraduate, and high school students with multi-faceted expertise in environmental microbiology, biochemistry, chemical catalysis, analytical chemistry, and sustainable chemistry, essential to solving environmental pollution problems. The research outcomes and outreach activities to local communities and stakeholders will promote a deeper and more accurate understanding of “forever chemicals” and provide new insights into the environmental fate and cost-effective treatment of PCFAS. To fill the critical knowledge gap of dehalogenation mechanisms regarding the understudied microbial dehalogenating reactions, this project will first systematically examine the dechlorination and defluorination activities of PCFAS structures by bacterial cultures, then identify and validate the biomolecules responsible for the dechlorination reactions that can trigger substantial defluorination. Lastly, reaction mechanisms and roles of dechlorination in defluorination will be further elucidated at the molecular level using the identified biocatalysts and biomimetic reactive species. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.