Researcher(s)
- Aubryanna Jarchow, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Mark Blenner, CBE, University of Delaware
- Kevin Solomon, CBE, University of Delaware
Abstract
The widespread global use of plastics has become a major source of pollution that urgently requires better solutions. Biological recycling addresses key limitations of traditional methods by enabling highly selective recycling. While this approach is industrially viable for Polyethylene Terephthalate (PET), a plastic with hydrolyzable oxygen groups, it faces significant barriers when applied to other common plastics. Specifically, Low-Density Polyethylene (LDPE) features a recalcitrant carbon-carbon backbone that makes biological degradation far more challenging.
Promisingly, yellow mealworms can deconstruct LDPE when their gut microbiome is intact. To understand the mechanism for this degradation, it is necessary to define the functions of the mealworm gut and the individual microbes within it. Because oxidation initiates LDPE breakdown, we first screened bacterial isolates for their ability to enzymatically oxidize LDPE using Fourier Transform Infrared (FTIR) spectroscopy. We then grew bacteria capable of oxidation in the presence of surfactants to understand their role in the mealworm gut. We compared two synthetic surfactants, Sodium Dodecyl Sulfate (SDS) and TritonX-100, with two naturally occurring gut components, gut supernatant and the fungus Aspergillus fumigatus. Gut supernatant has been shown to act as a natural surfactant, while A. fumigatus can flocculate plastic in solution. These forms of emulsification increase microbial-plastic interactions, aiding in biofilm formation. This can potentially increase microbial oxidation of LDPE, which would support the need for an emulsifying agent in a synthetic microbial community capable of degrading LDPE.
This study aims to discover the necessary functional roles required to degrade LDPE, facilitating the bottom-up construction of a synthetic community capable of degradation. Building this community will establish an effective method for biologically degrading LDPE, an important tool for establishing improved recycling infrastructure to reduce plastic pollution.