Exploring polyethylene degrading capabilities of bacteria using bioprospecting and synthetic biology

Plastic waste is a massive global problem, causing significant environmental concerns on land and in aquatic environments. Of the > 390 million tonnes of plastics produced in 2021, ~27% was polyethylene (PE), which is particularly difficult to break down and currently is not readily recyclable. Fortunately, larvae of the beehive pest Galleria mellonella are known to efficiently consume PE, but little is known about how this occurs. My first aim of this thesis was to isolate and identify bacteria in the G. mellonella larvae microbiome potentially driving PE degradation. By feeding larvae a PE diet, culturing larval homogenate on PE-containing agar plates and further differential plating, I successfully isolated candidate PE degrading bacteria and used 16S PCR for species identification. Secondarily, I set out to assess the validity of the most well studied PE degrading gene and explore potential new PE-degrading genes, identified previously in my laboratory. For this, I synthesised gene constructs of potential PE-degrading genes and introduced them into non-PE degrading E. coli. For both aims, PE-degradation ability was assessed using various microscopy and chemical methods. Together these approaches provided insight into the PE degradation potential of bacteria, laying a groundwork for further experimentation.