Laccase based per- and polyfluoroalkyl substances degradation: Status and future perspectives

Per- and polyfluoroalkyl substances (PFAS) with stable carbon-fluorine bonds are used in a wide range of industrial and commercial applications. Due to their extreme environmental persistence, PFAS have the potential to bioaccumulate, cause adverse effects, and present challenges regarding remediation. Recently, microbial and enzymatic reactions for sustainable degradation of PFAS have gained attention from researchers, although biological decomposition of PFAS remains challenging. Surprisingly, laccases, the multi-copper oxidases produced by various organisms, showed potential for PFAS degradation. Mediators play key roles in initiating laccase induced PFAS degradation and defluorination reactions. The laccase-catalyzed PFAS degradation reactions are relatively slower than normal biocatalytic reactions and the low activity of native laccases constrains their capacity to complete defluorination. With their low redox potential and narrow substrate scope, an innovative remediation strategy must be taken to accelerate this reaction. In this review we have summarized the status, challenges, and future perspectives of enzymatic PFAS degradation. The knowledge of laccase-based defluorination and the molecular basis of the reaction mechanisms overviewed in this study could inform future applications of laccases for sustainable PFAS remediation.