Scientists at the American Chemical Society’s fall conference in 2023 introduced eco-friendly bioplastic generated from soldier flies. Karen Wooley and her team are extracting chitin from black soldier flies and turning it into valuable bioplastics known as chitosan. This biodegradable plastic can absorb a lot of water and could be used to help with floods and droughts. The process aligns with a circular economy, utilizing insects to break down plastics and create new materials from them.
Just imagine harnessing the power of insects to extract chemicals that can be used to create environmentally friendly plastics, which can then be easily decomposed by these very same bugs. This idea is actually more plausible than it may initially appear. Scientists discussed advancements in extracting and refining chemicals from insects and turning them into useful bioplastics.
The researchers unveiled their innovative discoveries at the American Chemical Society (ACS) fall conference 2023. Karen Wooley, Ph.D., the project’s principal investigator, said, “For 20 years, my group has been developing methods to transform natural products — such as glucose obtained from sugar cane or trees — into degradable, digestible polymers that don’t persist in the environment. But those natural products are harvested from resources that are also used for food, fuel, construction, and transportation.â€
Karen Wooley searched for other sources that didn’t have these competing applications. Her colleague, Dr. Jeffery Tomberlin, has suggested an innovative way to make use of waste products by utilizing those derived from farming black soldier flies. This emerging industry, which he has actively contributed to, holds immense potential.
This summer, the team will start a project to break down chitin into glucosamines, which are its individual components. These small sugar molecules are used to create bioplastics like polycarbonates and polyurethanes, which are typically made from petrochemicals.
The black soldier flies are not only rich in useful compounds like proteins, DNA, fatty acids, lipids, and vitamins, but the group also intends to utilize them as valuable starting materials. These chemical building blocks are used to create products that are designed to decompose or break down when discarded, thereby avoiding any contribution to the existing issue of plastic pollution.
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Professor Wooley’s vision aligns the process with the sustainable, circular economy concept. She said, “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. So the insects would not only be the source, but they would also then consume the discarded plastics.â€
The immature insects, with their larvae filled with a variety of proteins and other nutrient-rich compounds, are now being extensively cultivated to serve as animal feed and to efficiently manage waste disposal. On the other hand, once their breeding days are over, adults have a relatively short life span and are subsequently cast aside. But adult soldier flies are being used for making bioplastic.
Professor Wooley’s team used the adult remains suggested by Jeffery Tomberlin to start their project. Cassidy Tibbetts, a graduate student working on the project in Wooley’s lab at Texas A&M University, said, “We’re taking something that’s quite literally garbage and making something useful out of it.â€
In the process of bioplastic generated from soldier flies, Tibbetts found chitin to be a significant part of the dead flies. This non-toxic polymer, made from sugar, strengthens the exoskeleton of insects and crustaceans. Manufacturers currently extract chitin from shrimp and crab shells for different purposes. Tibbetts has been using similar techniques to extract and purify chitin from insect carcasses.
According to her, the chitin powder sourced from flies is potentially purer as it does not possess the usual yellowish hue or dense consistency found in the traditional product. Obtaining chitin from flies can avoid concerns about seafood allergies. While other researchers extract chitin or proteins from fly larvae, Prof. Wooley’s team stands out as the pioneering group to utilize chitin from discarded adult flies. Unlike the larvae, which are typically used for feed, this unique approach sets them apart.
Tibbetts is improving extraction techniques, while another graduate student, Hongming Guo, is converting purified fly chitin into a polymer called chitosan. He removes acetyl groups from chitin, exposing chemically reactive amino groups, which allows for functionalization and cross-linking. By following these steps, chitosan can be converted into valuable bioplastics like superabsorbent hydrogels; intricate polymer networks with the remarkable ability to absorb water.
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Guo developed a hydrogel that can quickly absorb 47 times its weight in water. According to Professor Wooley, this product has the potential to capture floodwater in cropland soil and gradually release moisture during future droughts. She further explains, “Here in Texas, we’re constantly either in a flood or drought situation, so I’ve been trying to think of how we can make a superabsorbent hydrogel that could address this. Since hydrogel is biodegradable, it will slowly release its molecular components as nourishment for crops.â€
