Fungal biotransformation of 6:2 fluorotelomer alcohol

Abstract

Fungal degradation of 6:2 fluorotelomer alcohol (6:2 FTOH, C 6 F 13 CH 2 CH 2 OH) by two wooddecaying fungal strains and six fungal isolates from a site contaminated with per-and polyfluoroalkyl substances (PFASs) was investigated. 6:2 FTOH is increasingly being used in FTOH-based products, and previous reports on the microbial fate of 6:2 FTOH have focused on bacteria and environmental microbial consortia. Prior to this study, one report demonstrated that the 6:2 FTOH biotransformation by the wood-decaying fungus, Phanerochaete chrysosporium, generated more polyfluoroalkyl substances, such as 5:3 acid (F(CF 2 ) 5 CH 2 CH 2 COOH), and diverted away from producing the highly stable perfluorocarboxylic acids (PFCAs). Most of the fungi (Gloeophyllum trabeum and isolates TW4-2, TW4-1, B79, and B76) examined in this study showed similar degradation patterns, further demonstrating that fungi yield more 5:3 acid (up to 51 mol% of initial 6:2 FTOH dosed) relative to other metabolites (up to 12 mol% total PFCAs). However, medium amendments can potentially improve 6:2 FTOH biotransformation rates and product profiles. The six fungal isolates tolerated up to 100 or 1,000 milligrams per liter of perfluorooctanoic acid and perfluorooctane sulfonic acid, and some isolates experienced increased growth with increasing concentrations. This study proposes that fungal pathways must be considered for the biotransformation of potential PFAS precursors, such as 6:2 FTOH, and suggests the basis for selecting proper microorganisms for remediation of fluoroalkyl-contaminated sites.

Microbial Defluorination of Unsaturated Per- and Polyfluorinated Carboxylic Acids under Anaerobic and Aerobic Conditions: A Structure Specificity Study

“…The 3-fluoro 5:3 acid formed from the preferred hydrogenation pathway in the anaerobic defluorinating enrichment was not detected during the aerobic biotransformation (Figure S23B–D). 6:2 FTUCA is a key biotransformation intermediate of 6:2 fluorotelomer alcohol (6:2 FTOH, a component of coating material in commercial products) under aerobic conditions by various microbial communities and microbial species. − ,,− Many of the previously reported TPs were also detected here (Figure S23B–D), and among them, C6a (PFHxA) and C5a (PFPeA) were two major ones. We also detected two new TPs (2H-PFHpA and 2H-PFHxA) (Figures S23D and S24), which were not reported in previous studies on 6:2 FTOH .…”

“…The biodefluorination of fluorinated compounds (mostly the polyfluorinated structures) has been previously reported. − The defluorination was typically initiated by HF elimination at the α and β positions for polyfluorocarboxylic acids ,,, or by desulfonation for polyfluorosulfonic acids. ,,, Compared to biotransformation of polyfluorinated compounds, convincing reports on microbial cleavage of C–F in perfluorinated structures are even fewer. ,, Based on fluoride formation and transformation product identification, our recent study has reported microbial reductive defluorination of two branched unsaturated per- and polyfluorinated carboxylic acids in an anaerobic enrichment . It suggested that the biotransformation and biodefluorination of fluorinated carboxylic acids (FCAs) might be structure-dependent and that the CC double bond could play an essential role in the reductive defluorination of FCA.…”

Structure-Specific Aerobic Defluorination of Short-Chain Fluorinated Carboxylic Acids by Activated Sludge Communities

“…Thus far, tremendous efforts have been invested in understanding the environmental fate and transport of FCAs using microcosms and microbial isolates. ,,, −, − In Table , we summarized the aerobic defluorination reported in the literature and this study for C 2 –C 10 FCAs and the alcohol precursors oxidizable to carboxylic acids. In the table, all defluorinated structures share a common feature: a functional group subject to enzymatic defluorination or nondefluorinating reactions that form unstable intermediates with fluoroalcohol moieties causing spontaneous C–F cleavage.…”

Droplet digital microfluidic system for screening filamentous fungi based on enzymatic activity

“…The effect of the carbon source in the droplet media on growth is limited, given that when droplets were incubated (27 °C, 2 days) in minimal media without any carbon source, we found several C. rosea spores germinating and developing hyphae. This can be explained by spore germination being mainly dependent on the presence of water and oxygen 45 , or C. rosea could have a mechanism to access the carbon chain of fluorinated surfactants in the HFE oil since the ability to degrade fluorinated compounds has been demonstrated for other fungi [46][47][48] .…”