Advances in bioremediation strategies for PFAS-contaminated water and soil

Abstract

Per- and poly-fluoroalkyl substances (PFAS) are emerging contaminants, posing adverse impacts on water and soils due to their persistence, chemical transformations, and bioaccumulation. With over 15,000 different PFAS compounds being identified globally, their toxic effects and half-life spanning from 72 ​h to 8.5 years in humans are a serious concern. Bioremediation has emerged as an environmentally-friendly and cost-effective approach for PFAS degradation. However, there is still limited understanding of PFAS interactions with microorganisms and the roles of promising microbes in transforming PFAS into non-toxic end products. The knowledge about biotransformation of PFAS is essential to ameliorate the adaptation of microorganisms to local matrix and environment as well as to strengthen the natural enzymatic pathways and activities at a commercial scale, which is a major challenge. This review aims to address these gaps by providing a comprehensive analysis of recent developments in the bioremediation of PFAS-contaminated soil and water systems. The review focuses on the capabilities of phytoremediation, bioelectrochemical systems, and microbial species, including bacteria, fungi, and microalgae. Additionally, this study offers an in-depth overview of PFAS sources, their physicochemical characteristics, and their environmental fate and transport. Furthermore, it examines microbial metabolic activity, the formation of degradation intermediates, the role of co-metabolism, and the behaviour of microorganisms under PFAS stress as well as highlights future research directions. The key findings from this review include: 1) microbial community composition, field application, presence of co-substrate and cationic complexation govern biotransformation and fate of PFAS, 2) long chain PFAS are more susceptible to accumulate in the roots due to high hydrophobicity, and 3) algae-bacteria symbiotic relationships reduce microalgae growth inhibition and stimulates PFAS removal. Overall, this review emphasizes the potential of bioprocesses for large-scale PFAS bioremediation, contributing to environmental protection and mitigating the risks associated with PFAS contamination.