Engineering Pseudomonas putida into a degradation bio-factory for per- and poly-fluoroalkyl substances: A metabolic and evolutionary approach

• Applicant: Dr. Paul Matthay
• Subject Area: Biological Process Engineering ; Microbial Ecology and Applied Microbiology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 543786638

Our everyday life would be impossible without per- and polyfluoroalkyl substances (PFAS). This large group of chemicals consists of thousands of compounds, each characterized by numerous carbon-fluor bonds—the strongest bond known to organic chemistry. These bonds equip PFAS with industrially sought-after characteristics resulting in their widespread use as, for example, surfactants, solvents, pesticides as well as being vital in the manufacturing of electronics. Unfortunately, massive industrial implementation of PFAS comes with a heavy toll: the strong bonds make them virtually nondegradable, resulting in an enormous global PFAS contamination. Traces of PFAS have been found even in untouched regions of Antarctica, as well as in almost every blood sample taken in studies in Germany, Denmark, and the UK. Critically, PFAS pose numerous health risks including, but not limited to, kidney and liver damage, child and fetus developmental impairment, and suspected carcinogenic effects. Efficient degradation of PFAS thus represents an opportunity for significant societal and health benefits. Unfortunately, current physical and chemical degradation methods are costly and not applicable on large scales, underscoring the need for versatile alternative degradation methods to ameliorate this global health crisis. Through this project, I aim to identify a key alternative microbial degradation method. In search for appropriate degradation methods, biological degradation has been largely ignored, despite clear promise based on results using microbial communities or environmental isolated microbes obtained from contaminated environments. In this project, I will take a new approach for microbial PFAS degradation by engineering the model organism Pseudomonas putida to degrade and grow on PFAS molecules. P. putida has an abundance of genetic and physiological information available, facilitating genetic and metabolic engineering approaches, and unlike environmental microbes, P. putida is biosafety level 1 (rendering it harmless for humans and the environment, which is critical for future real-world applications). I will engineer P. putida using state-of-the-art genetic, metabolic, and evolutionary engineering techniques. Specifically, I will grow cells in the presence of various PFAS with and without other potential carbon sources to explore the evolutionary landscape and metabolic limits of the cells. Next, I will test appropriate PFAS and environments in large-sale evolutionary experiments, by continuously growing the cells in PFAS. Eventually mutations will arise that allow cells to remove fluor more efficiently and to grow on the released carbon. Identifying, reintroducing, and combining those mutations will not only allow us to understand microbial PFAS degradation but will additionally result in microbes able to degrade PFAS, illuminating a previously elusive pathway to combat the global PFAS health crisis.

• DFG Programme: WBP Fellowship
• International Connection: Japan
• Host: Professorin Paola Laurino, Ph.D.