Plastic-eating bugs
We just finished a study in the lab looking at whether beetles (Tenebrio molitor, aka mealworms) can eat plastic particles made from disposable surgical face masks. The results are promising! The beetles ate about 50% of the particles we fed them. Here are some photos and videos from the process.
From left to right (top to bottom) below: We melted and ground up polypropylene medical face masks. We added wheat bran and gelatin to the powder to make plastic granola. We then divvied up the granola into beakers.
From left to right (top to bottom) below: We melted and ground up polypropylene medical face masks. We added wheat bran and gelatin to the powder to make plastic granola. We then divvied up the granola into beakers.
We placed 20 mealworms into each beaker and waited until they ate all of the granola. We also had beakers that just contained wheat bran and mealworms, and beakers that just contained plastic granola and no mealworms.
The videos below show mealworms getting to know their dinner.
The videos below show mealworms getting to know their dinner.
|
|
|
At the end of the experiment, we weighed and then froze the surviving mealworms, weighed any leftover food, dissolved the frass (poop) and counted any plastic particles that were pooped out. The small granule-like particles in the beakers below are mealworm frass.
Overall, we were happy with how this study turned out. Previous studies had shown that these beetles can eat pure polypropylene or pure PLA (the other plastic we used) but nobody had yet shown that they could also eat microplastics that were derived from consumer products.
Although we are one step closer to figuring out how to safely biodegrade plastic waste, it would take 100 mealworms 4.5 months to biodegrade one face mask. At the height of the pandemic, we were using billions of face masks daily. Clearly the quest for plastic degradation strategies must go hand-in-hand with reductions in plastic manufacturing.
Photos below show from left to right (top to bottom): close up of mealworm frass; several beakers of frass at the end of the experiment, and discarded disposable face masks (and an orange peel) on UBC campus.
Overall, we were happy with how this study turned out. Previous studies had shown that these beetles can eat pure polypropylene or pure PLA (the other plastic we used) but nobody had yet shown that they could also eat microplastics that were derived from consumer products.
Although we are one step closer to figuring out how to safely biodegrade plastic waste, it would take 100 mealworms 4.5 months to biodegrade one face mask. At the height of the pandemic, we were using billions of face masks daily. Clearly the quest for plastic degradation strategies must go hand-in-hand with reductions in plastic manufacturing.
Photos below show from left to right (top to bottom): close up of mealworm frass; several beakers of frass at the end of the experiment, and discarded disposable face masks (and an orange peel) on UBC campus.
The paper: Gicole, S., A. Dimitriou, N. Klasios and M. Tseng. Biodegradation of medical facemasks by a widespread beetle species. To be submitted May 2024. Funding: Natural Sciences and Engineering Research Council (NSERC) to MT and the UBC Biodiversity Research Centre Undergraduate Diversity Research Grant to S.G. We thank Prof. Parisa Mehrkhodavandi for confirming the plastic type used in the face masks and Prof. Rachel Scholes for access to a vented oven. The University of British Columbia Vancouver campus occupies the traditional, unceded, and ancestral lands of the Musqueam