Synergistic Material-Microbe Interface toward Deeper Anaerobic Defluorination

Per- and polyfluoroalkyl substances (PFAS), particularly the perfluorinated ones, are recalcitrant to biodegradation. By integrating a reductively defluorinating enrichment culture with biocompatible electrode materials in an electrochemical system, deeper defluorination of a C6 perfluorinated unsaturated PFAS was achieved compared to the biological or electrochemical system alone. Two types of synergies in the bioelectrochemical system were identified: (i) the microbial-electrochemical in-series defluorination and (ii) the electrochemically enabled microbial defluorination of intermediates at the cathode. Specific cathode microorganisms were enriched, which likely involved in the electrochemically enhanced biodefluorination. The synergies at the material-microbe interface surpassed the limitation of microbial defluorination and further turned the biotransformation end-products into deeper defluorination products, which could be more biodegradable in the environment. It reveals a strong promise of the sustainable material-microbe hybrid system, which could be driven by renewable electricity in PFAS bioremediation and warrants future research to optimize the system and maximize its performance.