Human Intestinal Microbiota Composition Shapes Model Polyfluoroalkyl Substance Biotransformation

6:2 polyfluoroalkyl phosphate diester (6:2 diPAP) is a prevalent environmental contaminant to which humans are regularly exposed. Environmental microbes can biotransform 6:2 diPAP, and the human gut microbiome can biotransform its congener, 8:2 monoPAP. While the human gut microbiome is highly variable between individuals, potential variability in PAP biotransformation has yet to be assessed. We address this gap using six cohorts (A-F) to examine in vitro biotransformation of 6:2 diPAP by the human gut microbiome. Biotransformation pathways of 6:2 diPAP and their connections to the composition of microbial taxa were assessed using gas chromatography mass spectrometry (GC-MS), liquid chromatography tandem mass spectrometry (LC-MS/MS) and 16S rRNA amplicon sequencing. All cohorts biotransformed 6:2 diPAP but differed in their downstream perfluoroalkyl acid (PFAA) profiles, suggesting diverse biotransformation pathways. Microbial community analysis showed similar alpha diversity across cohorts, while the degree of difference between cohorts varied. The analysis confirmed the initial composition of each cohort's microbial community had a bearing on products stemming from 6:2 diPAP transformation, likely driven by low-abundance microbial taxa. These findings underscore the complexity of microbe-mediated polyfluoroalkyl substance (PFAS) transformation and highlight the need for mechanistic studies that identify the genetic controls governing PFAS transformations in the gut microbiome.