Theme: 07. Per- and Polyfluorinated Alkyl Substances (PFAS)

Topic Area: 7g. PFAS and Bugs: The Search Continues

Formatted Title:

Biotransforming the “Forever Chemicals”: Trends and Insights from Microbiological Studies on PFAS

Background/Objectives:

Per- and polyfluoroalkyl substances (PFAS) are recalcitrant organic chemicals with human and environmental health implications. Many recent research efforts have been dedicated to microbial biotransformation in the hopes of developing PFAS treatment technologies using microorganisms as catalysts for their defluorination and transformation to non-toxic byproducts. Critical reviews typically highlight the relative successes of PFAS biotransformation and biodegradation while studies with limited or no PFAS biotransformation receive less emphasis or inclusion in scientific discussions.

Approach/Activities:

The development of microbial treatment for PFAS and the understanding of the fate of PFAS in the environment must be equally informed by successes and research challenges. Here, we performed a meta-analysis by extracting and standardizing quantitative data from 97 microbial PFAS biotransformation studies and comparing outcomes via statistical tests. Studies were divided by experimental conditions to understand which conditions are most likely to render microbial PFAS biotransformation.

Results/Lessons Learned:

Most of the studies with evidence of PFAS biotransformation were conducted under aerobic conditions, while only a few studies carried out under anaerobic conditions showed evidence biotransformation. Broadly, this meta-analysis indicated that likelihood of PFAS biotransformation was higher under aerobic conditions, in experiments with defined or axenic cultures, when high concentrations of PFAS were used, and when the tested PFAS contained fewer fluorine atoms in the molecule. Anaerobic biodegradation of PFAS with well-defined electron acceptors, electron donors, carbon sources, and oxidation-reduction potential is missing in the literature. Additionally, an analysis of the full range of PFAS-biotransformation products is needed to verify biotransformation and to build fluorine, carbon, and electron balances. The potential for biotransformation for many PFAS has yet to be experimentally verified or reported. Most biotransformation research emphasis to date has been on 8:2 fluorotelomer alcohol (8:2 FTOH), 6:2 fluorotelomer alcohol (6:2 FTOH), perfluorooctanesulfonic acid (PFOS), and perfluorooctanoic acid (PFOA). We provide a comparison of the more mature field of microbial dechlorination to the developing field of microbial defluorination in order to identify disparities and how microbial defluorination experimentation could benefit from recognizing the limiting factors known to control microbial dechlorination outcomes. We additionally provide recommendations to which may help standardize the PFAS microbial biotransformation literature in order to facilitate iterative and comprehensive experimentation that may hasten the development of fundamental knowledge essential to the development of biotechnologies for PFAS treatment.

Alia Raderstorf

Affiliation

Track

Refine Results

(Group 2, Poster Board #88) Biotransforming the “Forever Chemicals”: Trends and Insights from Microbiological Studies on PFAS