Black soldier flies are a good source of chemicals to make bioplastics. Credit: Cassidy Tibbetts
Key points:
- In new research, black soldier flies were used as a chemical source to make biodegradable plastics.
- Chitin from the flies transformed into useful bioplastics, including superabsorbent hydrogels.
- This technique may lead to a sustainable economy where insects are the source of plastics and consume the waste plastic.
At the 2023 Fall American Chemical Society (ACS) meeting, researchers described how they are using the waste products left over from farming black soldier flies to develop degradable digestible polymers.
The larvae of these flies contain many proteins and other nutritious compounds, so the immature insects are increasingly being raised for animal feed and to consume wastes. However, the adults have a short life span after their breeding days are over and are quickly discarded.
Using the dead adults as a starting point, researchers found chitin—a non-toxic, biodegradable, sugar-based polymer—in their exoskeleton. The Texas A&M team then used ethanol rinses, acidic demineralization, deproteinization and bleach decolorization to extract and purify it. The final step was to strip chitin’s acetyl groups to convert it to the chitosan polymer, which has a variety of potential functions.
The researchers ultimately transformed chitin into superabsorbent hydrogels that can absorb 47 times their weight in water in just 1 minute. The product could be used in cropland soil to capture floodwater and then release moisture in times of drought.
This summer, the Texas A&M scientists embarked on a project to break down chitin into its monomeric glucosamines. These small sugar molecules can then be used to make bioplastics, such as polycarbonates or polyurethanes—which are traditionally made from petrochemicals.
In the further future, the researchers hope to find other uses for black solider fly materials, including proteins, DNA, fatty acids, lipids and vitamins. These materials, along with chitin, can be used to develop products that degrade or digest when discarded.
“Ultimately, we’d like the insects to eat the waste plastic as their food source, and then we would harvest them again and collect their components to make new plastics,” said study author Karen Wooley, professor at Texas A&M University.