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Microbial Dehalogenation of 3,5,6-Trichlorooctafluorohexanoic Acid under Different Reducing Conditions
Changjie Zhao1,2, Longlong Zhang1,2, Yanlong Wang1,2
1College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Environmental Science & Technology
|June 4, 2026
Summary
Chlorinated polyfluoroalkyl substances (Cl-PFAS) show promise as alternatives to legacy PFAS. Microbial defluorination of CTFE3 was most effective under nitrate- and sulfate-reducing conditions, highlighting hydrolytic dechlorination for Cl-PFAS remediation.
Area of Science:
- Environmental Chemistry
- Microbial Ecology
- Bioremediation
Background:
- Chlorinated polyfluoroalkyl substances (Cl-PFAS) are emerging alternatives to legacy PFAS, offering enhanced reactivity and degradability.
- Understanding Cl-PFAS transformation under reducing conditions is crucial for environmental risk assessment and remediation strategies.
Purpose of the Study:
- To investigate the microbial dehalogenation of 3,5,6-trichlorooctafluorohexanoic acid (CTFE3), a representative Cl-PFAS.
- To characterize CTFE3 transformation pathways under various environmentally relevant reducing conditions (nitrate-, sulfate-, iron-reducing, and methanogenic).
Main Methods:
- Incubation of CTFE3 with microbial consortia under different anaerobic reducing conditions.
- Quantification of defluorination using analytical chemistry techniques.
- Metagenomic analysis to identify microbial communities and functional genes involved in biotransformation.
Main Results:
- Significant microbial defluorination of CTFE3 occurred across all tested reducing conditions.
- Higher defluorination efficiencies (∼60%) were observed under nitrate- and sulfate-reducing conditions compared to iron-reducing and methanogenic conditions (∼30%).
- Hydrolytic dechlorination was identified as a key pathway, particularly under nitrate- and sulfate-reducing conditions, with enrichment of associated genes and specific microbial taxa.
Conclusions:
- Reducing conditions significantly influence Cl-PFAS transformation pathways.
- Hydrolytic dechlorination is a viable and effective microbial pathway for the extensive defluorination of CTFE3.
- Specific microbial taxa possessing both dehalogenation and relevant redox-activity genes are likely key players in Cl-PFAS bioremediation.
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