Confirming Degradation of Polyethylene by Galleria mellonella Through Fluorescence

Plastic has been an integral part of our everyday lives causing not only its exponential increase in production but also its increase in waste within our environment. Plastic in the environment has a known negative impact on all organisms, including ourselves. Although there have been methods (e.g. recycling, phytoremediation) to mitigate the plastic problem, these methods have not been effective in solving the issue. The greater waxworm, Galleria mellonella is capable of degrading polyethylene at considerably higher rates than microorganisms with the same ability, meaning the larva provides potential for a new bioremediation technique. The natural diet of G. mellonella is comprised of honeycomb and beeswax, though whether the larvae are capable of metabolizing polyethylene by similar mechanisms is largely debated. Additionally, the role of their gut microbiome in the degradation and possible metabolism of polyethylene is not fully understood. To determine whether G. mellonella can metabolize polyethylene, we will expose larval G. mellonella to various polymer diets including treatments that incorporated fluorescent polyethylene microspheres. After ingestion of polymer diets, we will observe larvae intestines and fat bodies under a fluorescent microscope to establish the rate of uptake, degradation, and absorption into the caterpillar body. Furthermore, the gut microbiome ecology will be determined through RNA sequencing. Simultaneously, the experiment will be repeated with larvae that lack an intact gut microbiome. We will discuss our findings in the context of bioremediation and the natural history of the organism.