Enhancing the understanding of microbial transformation of polyfluoroalkyl chemicals and microbial defluorination

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Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are widely found in soil and sediment, surface and ground water, as well as our drinking water systems. PFASs, especially the ones originated from aqueous film-forming foams (AFFFs), are a significant and constant threat to groundwater quality. Since only a few PFASs among several thousand used in commerce are regulated in Canada, environmental and public health protection agencies are urgently gathering the data required to address the safety and regulatory questions related to many PFASs. Impacted communities worldwide are searching for effective solutions to remediate polluted soil and water systems. Despite multiple C-F bonds in their structure, most of the polyfluoroalkyl chemicals can undergo biotransformation and even defluorinate. Transformation products are found to be complex; some are persistent while others are highly toxic. The failure to identify and monitor many transformation products could lead to a great uncertainty on the environmental impact of PFASs. Therefore, to develop effective strategies for management and remediation of thousands of PFAS contaminated sites, improved understanding of transformation pathways present in microbial systems is warranted. The identity, diversity, and richness of microorganisms, as well as functional genes that are responsible for such transformations, must be explored. ******The overall goal of the research is to elucidate novel processes and mechanisms by which microorganisms break down C-F in polyfluoroalkyl chemicals, and to discover the diversity and identity of such microorganisms. One major focus of the work in my groups is to establish new biotransformation rules through experimental work using model PFASs and to develop prediction capability that can be applied to elucidating the environmental fate of several hundred PFASs detected in the environment. In the meantime, we will use mixed and pure bacterial culture to investigate the mechanisms and limitations of “one-carbon removal pathways”, which microorganisms employ to defluorinate PFASs. We will also be working towards identifying the microbes involved in degrading polyfluoroalkyl chemicals in the environment through a culture-independent technique of stable-isotope probing. The interdisciplinary research linking environmental chemistry with microbiology is necessary for generating the insight into the interactions of PFASs with microorganisms or enzymes. The proposed research program will prioritize the training of HQP using an integrated multidisciplinary approach and a collaborative training environment. At least 1 postdoctoral fellow, 2 Ph.D., 2 Master's and 5 undergraduates will be receiving training through this program and obtain the skills and visions that are needed for the Canadian workforce in emerging areas of engineering and applied science.*****