Elucidating the Mechanism of PFOA Regulation of Biofilms in Aquatic Systems at Gene and Metabolic Levels

Perfluorooctanoic acid (PFOA) is prevalent in aquatic ecosystems and exhibits significant toxicity to aquatic organisms. Microorganisms can adhere to the surfaces of submerged plants, forming complex extracellular structures referred to as attached biofilms. However, the mechanisms underlying the regulation of biofilm formation by PFOA remain unclear. This study cultured plant-attached biofilms under PFOA stress to investigate the mechanisms by which PFOA regulates biofilm formation, utilizing metagenomics and metabolomics. Results show that the biofilm structure was significantly altered under PFOA exposure, characterized by an increase in polysaccharide and protein content. Furthermore, PFOA bound to proteins within extracellular polymeric substances contributes to a reduction in PFOA toxicity. PFOA regulates biofilm formation by modifying the content of signaling molecules and the abundance of genes (bapA and ABC.PE.S) associated with quorum sensing, establishing a natural barrier against the toxic effects of PFOA. In addition, PFOA was found to inhibit the metabolism of linoleic and linolenic acids, thus indirectly promoting the formation of biofilms, which allowed microbial aggregation and coresistance to the toxic effects of exogenous pollutants. This study provides a comprehensive understanding on the mechanisms by which PFOA regulates biofilm formation, which is crucial for enhancing our understanding of microbial processes in aquatic ecosystems.