Mobilizing the PFAS-Degrading Gene from Acidimicrobium Sp. Strain A6: A Strategy for Breaking Down PFAS in Anaerobic Digesters

Abstract

Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants that have been associated with adverse health effects. While Acidimicrobium sp. strain A6 demonstrates the ability to degrade PFAS, it is unsuitable for industrial applications. This thesis is focused on investigating whether a gene from Acidimicrobium sp. strain A6, encoding a reductive dehalogenation enzyme capable of degrading per- and polyfluoroalkyl substances (PFAS), can be successfully transformed into a faster reproducing microbial host. The long-term aim is to design a plasmid that can be transferred into the bacteria Shewanella oneidensis, enabling the gene to propagate through horizontal gene transfer within diverse microbial communities. PFAS pose significant challenges to remediation efforts as they are energy-intensive and expensive to degrade. Here, we show that expression of the A6-derived gene in S. oneidensis resulted in enhanced bacterial growth in PFAS-containing environments, indicating a possible functional response to PFAS exposure. With the insert, S. oneidensis was able to grow in high concentrations of PFOA, a response not observed in strains lacking the gene. While PFAS did not serve as a sole electron acceptor, the enhanced anaerobic growth suggests that its presence may supplement metabolism. These findings demonstrate the potential of harnessing faster-growing microbial hosts for PFAS bioremediation through gene mobilization. I anticipate this research to be a starting point for designing diverse microbial communities capable of degrading PFAS, with the ability to disseminate the degradation gene through horizontal gene transfer.