Researchers Discover Novel Enzyme from Bacteria That Can Break Down PFAS Compounds
Researchers have purified and characterized a novel enzyme from the bacterium Achromobacter mucicolens that can cleave carbon-fluorine bonds in PFOA, a common 'forever chemical,' releasing measurable fluoride within 24 hours. The enzyme, a haloacid dehalogenase type II (HAD-II), was discovered in PFAS-contaminated lake sediment and suggests microbes may be actively adapting to degrade these persistent pollutants. The finding offers a potential new avenue for biological PFAS remediation that does not require the energy-intensive chemical or thermal processes currently in use.
A study posted to the preprint server bioRxiv describes the isolation and characterization of a HAD-II enzyme from Achromobacter mucicolens, a bacterium recovered from PFAS-contaminated lacustrine sediment. In recombinant enzyme assays, the system released approximately 0.55 ppm fluoride from a 5 ppm solution of perfluorooctanoic acid (PFOA) within 24 hours, representing roughly a 17% defluorination yield. Structural and phylogenetic analyses show the enzyme belongs to a deeply divergent lineage, sharing only 25% sequence identity with a previously characterized homologue from Delftia, yet retaining the core catalytic fold. Molecular docking experiments helped explain this functional divergence: PFOA adopts a productive binding orientation near the conserved catalytic residue Asp15 in the Achromobacter enzyme, while the Delftia counterpart positions PFOA non-productively outside the active site. The authors argue the discovery provides evidence of real-world microbial adaptation to PFAS contamination and represents a new paradigm for targeted, cell-free biological remediation of these highly persistent compounds.
What's missing
As a preprint, this work has not yet undergone peer review. Key limitations include the modest defluorination yield (17%) achieved under controlled lab conditions, with no data yet on performance in complex environmental matrices such as actual contaminated water or soil. The study does not address whether the enzyme can act on other PFAS compounds beyond PFOA, the enzyme's stability or scalability for practical remediation, or potential toxic intermediates that may be generated during partial defluorination.
What different sources said
- bioRxivCenter
Discovery of a novel dehalogenase from Achromobacter mucicolens for PFAS defluorination
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