Recent advances in microbial and bioelectrochemical strategies for degradation of per- and polyfluoroalkyl substances: mechanisms, limitations, and research opportunities.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants characterized by strong carbon-fluorine bonds, making them resistant to conventional degradation methods. Their widespread detection in soil, water, and living organisms, coupled with significant potential health risks, has necessitated the development of effective remediation strategies. This review provides a detailed overview of recent advances in biotechnological approaches for PFAS degradation, with a focus on microbial and bioelectrochemical systems (BESs). Microbial species such as Pseudomonas and Acidimicrobium strains have demonstrated the ability to degrade PFAS under both aerobic and anaerobic conditions. Key enzymes, including dehalogenases and oxygenases, play a critical role in catalyzing the breakdown of PFAS. BESs technologies, including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs), offer innovative solutions by combining microbial activity with electrochemical processes to enhance PFAS removal efficiency. Advanced BESs configurations, such as constructed wetland-MFCs, have further demonstrated the potential for enhanced PFAS removal through electrode adsorption and plant uptake. Despite significant progress, challenges remain, including PFAS toxicity, the complexity of environmental matrices, incomplete mineralization, scalability, and public safety concerns. Addressing these issues will require advancements in genetic engineering to develop robust microbial strains, optimization of BESs configurations, and integration with other advanced treatment technologies like advanced oxidation processes. Additionally, refining environmental factors such as pH, temperature, and the presence of humic substances is crucial for maximizing degradation efficiency. Future research should focus on scaling laboratory successes to field-scale applications, developing real-time monitoring tools for degradation processes, and addressing regulatory concerns. Through continuous innovation, biotechnological solutions offer a promising pathway to sustainable and effective PFAS remediation, addressing both environmental and public health concerns.