Researchers from Saint Petersburg State University of Electrical Engineering LETI have observed that Zophobas morio larvae can completely break the benzene rings that compose expanded polystyrene foam. This finding was shared with socialbites.ca.
Among the most hopeful approaches to reducing plastic waste is using living organisms to break it down. Scientists initially tested how effectively Zophobas morio larvae could tackle this challenge, and they discovered that the larvae do not merely accumulate plastic; they also recycle it.
When Zophobas morio larvae crowd together, they delay pupation as an evolutionary defense against cannibalism. Consequently, at sufficiently high population densities, the insects can remain in the caterpillar phase for several months, typically 3 to 4 months, before reaching their natural end.
In the experiment, the insects were divided into three groups. The first served as a control, receiving a diet of grains, fruits, and vegetables to supply all the nutrients needed for normal life functions. The second group fed exclusively on polystyrene foam, while the third group received no food at all. Researchers then monitored survivorship and weighed polystyrene samples over a month, counting the number of surviving individuals in each group.
In the well-nourished control group, both dead specimens and exuviae, the chitin membranes shed during molting, remained largely intact. The second group, Zophobas morio, resorted to cannibalism when plastic did not provide all required nutrients. In the third group, cannibalism occurred roughly twice as often as in the second group, indicating the severity of nutrient deprivation in the absence of edible material. These observations were reported by the study’s authors (LETI research, 2024).
Further analysis involved examining the plastic and the caterpillar feces with Fourier transform infrared spectroscopy. Because benzene rings are the principal component of polystyrene, the starting material showed distinct spectral peaks corresponding to benzene. However, these peaks were absent in the fecal spectra of the foam-fed larvae, suggesting substantial transformation.
The researchers concluded that Zophobas morio not only alters polystyrene foam but also breaks the benzene ring. It appears that enzymes produced by bacteria in the larvae’s digestive system—not the larvae themselves—are responsible for digesting the plastic. The next step is to identify this bacterial group, isolate them, and recreate the conditions needed for a bioreactor to process foam waste efficiently (LETI research, 2024).
Looking ahead, scientists plan to extend this work to other forms of plastic, with a focus on polyethylene and ethylene vinyl acetate to gauge broader applicability.
In related developments, researchers in Kuzbass explored the feasibility of silk-based patches for storage containers, signaling ongoing interest in bio-inspired materials and sustainable packaging solutions.