Microbial Remediation of Per- and Polyfluoroalkyl Substances in Water: Mechanisms, Biotransformation, and Future Perspectives

Per- and polyfluoroalkyl substances (PFAS) are synthetic fluorinated compounds widely recognized for their stability and persistence in the environment. These characteristics make PFAS valuable in many applications but also pose serious health risks because they do not break down easily. These chemicals can accumulate in living organisms and persist in water systems. PFAS typically transfer from water to other media rather than being completely degraded by conventional treatment technologies such as adsorption and membrane filtration. Chemical degradation techniques, i.e., advanced oxidation processes or electrochemical conversions, require harsh reaction conditions, which make them unsustainable. Microbial degradation offers a green, sustainable alternative for PFAS remediation in water. This review critically analyzes advances in the use of bacterial, fungal, and microbial consortia for PFAS transformation via reductive and oxidative defluorination and/or metabolic reactions. Later, the influence of PFAS structural attributes, i.e., chain length and functional head groups, on microbial activities has been discussed. In the following section, the current progress toward the complete mineralization of PFAS is evaluated. Considering the critical evaluation of microbial degradation processes, several research gaps have been identified, including the lack of detailed mechanistic studies of enzymatic degradation pathways, the need to optimize microbial systems for the sustainable degradation of PFAS, and the integration of biological approaches with other technologies to achieve complete PFAS mineralization. The most important is scaling up microbial techniques by cost evaluation of the process to compete with other physicochemical techniques.