Engineering Microbial Communities for LDPE Degradation

• Lauren Applegate, Biochemistry, University of Maryland
• Agni Miraji-Khot, Chemical Engineering, University of Delaware

• Mark Blenner, Chemical and Biomolecular Engineering, University of Delaware
• Kevin Solomon, Chemical and Biomolecular Engineering, University of Delaware

Plastic pollution poses a significant global threat, with more than 90 percent of plastic waste left to accumulate in the environment. Even when they are recycled instead, current plastic recycling methods are energy-intensive and result in low-quality products. Upcycling via biological systems prevents an economical alternative by transforming plastic waste into valuable products. Yellow mealworms have been observed to consume low-density polyethylene (LDPE), a certain type of plastic that constitutes a significant portion of plastic waste. This consumption is possible because of the microbial communities in their digestive system that can break down LDPE chains. While samples of the full mealworm gut can degrade LDPE, individual bacterial isolates cannot. Thus, we sought to identify combinations of various microbial species in the mealworm gut that had optimal plastic degradation ability. To measure the ability of communities to consume plastic waste, species were grown with plastic as their only carbon source, and then treated with a dye that fluoresces in the presence of respiratory activity. This method demonstrated that a fungus species from the mealworm gut enhances the ability of bacteria to consume plastic, without consuming the plastic itself. A certain bacterial strain was also identified as more effective than others at plastic consumption. Additionally, the method of plastic consumption detection was refined significantly for future use. Improving understanding of interspecies interactions in the mealworm gut will assist in the development of optimized biological systems for plastic degradation and upcycling.