(172f) Discovery of Enzymes for Biodegradation of Polyethylene and Polypropylene

Biological degradation of plastics has the potential to provide a distributed, cost effective, and low energy means of dealing with our society’s plastic waste problem. Since the heterogeneity and distributed nature of plastic waste are two of the largest practical challenges to large-scale plastic recycling and upcycling, biological systems are attractive for their ability to funnel heterogeneous substrates into central metabolites, and the ability to operate in a distributed manner. Our prior work has identified microbial communities and microbes associated with plastic biodegradation from the yellow mealworm. This talk focuses on the prediction, and identification of enzymes that can degrade the polyethylene and polypropylene. We have screened a diverse set of enzymes that from families enriched in the metagenome assembled genomes of microbial isolates that demonstrated superior growth using plastic beads as a substrate. Enzymes were heterologously expressed, and tested for activity on different plastic films. The activity of these enzymes was measured using FTIR, gel permeation chromatography, and differential scanning calorimetry. Physical changes in film surface were measured using SEM and AFM. FInally, we have characterized the plastic degradation intermediates using gas chromatography and mass spectroscopy. We have further identified additional enzymes that derive from outside of the gut that have demonstrated potential for plastic degradation. Finally, we will describe progress using activity-based protein profiling to identify additional plastic-degradation enzymes from even unculturable microbial communities.