Enhancing Plastic Degradation Through Mealworm Gut Enzyme Cocktails and Cascades

• Megan Tarr, Chemical Engineering, University of Delaware

• Mark Blenner, Chemical Engineering, University of Delaware

Plastic, widely used for its affordability and durability, presents a severe threat to the environment, with the lack of infrastructure for recycling and other degradation methods resulting in its accumulation in landfills. In order to minimize alarming effects, researchers are finding innovative ways to reduce plastic debris. Previous studies have shown that mealworms have the ability to break down plastic through consumption, giving hope for a new method of plastic upcycling. Through experimentation, it has been found that the microbes within mealworm guts show promise for expressing enzymes capable of degrading plastic. To help enhance this degradation process, enzyme assay cocktails and cascades were performed using a mealworm gut metagenome and salvia proteomes. In order to determine if these enzymes degraded plastic better in combination, various enzyme cocktails were dosed onto LDPE film. A similar cascade assay was performed with each enzyme and aldehyde dehydrogenases to discover if they are able to increase plastic degradation with these cofactors. After dosing the enzymes, either alone or in combination with Semi-ALDH or ALDH, onto LDPE films for five days, Fourier-transform infrared spectroscopy (FTIR) was used to detect any chemical changes in the film. Typically, plastic degradation is signified through an carbonyl bond absorbance peak. Unexpectedly, there were no carbonyl peaks in any of the cocktail assays, suggesting that enzyme activity is more effective alone. The cascade assays also did not demonstrate absorbance at the expected wavelength for degradation, implying that aldehyde dehydrogenases inhibit enzyme activity. Due to unexpected absorbance peaks that suggest the presence of ether groups in both the cocktail and cascade assays, this experimentation is being repeated. In the future, cocktail and cascade testing will continue, with the combination of dyp-peroxidase enzymes and more cofactors to optimize the degradation process.