Scientists turn dead flies into biodegradable plastic
According to new research, the hard shells of insects — an abundant resource that otherwise goes to waste — can be used to engineer a type of eco-friendly material which is circular and doesn’t persist in the environment.
Plastic pollution is a huge problem.
With 30 million metric tonnes of the stuff being dumped on land annually, almost 50 million metric tonnes of it burned, and another 11 million washed away by the sea (not to mention it takes over 1000 years to degrade), it’s been wreaking havoc on our health and the planet’s for decades now.
Seeking to combat this and offer us an alternative material that isn’t quite so detrimental to the Earth’s wellbeing and our own, is a team of researchers at Texas A&M University.
For two decades they’ve been trying to develop methods of transforming natural products such as glucose obtained from sugar cane or trees into degradable, digestible polymers that don’t persist in the environment.
Not only this, but they’ve been determined to find a resource without competing uses like food, fuel, construction, or transportation, and recently it seems they have succeeded.
Presenting the findings at the American Chemical Society (ACS), principal investigator Karen Wooley and her colleagues have managed to turn dead black soldier flies, an abundant resource that otherwise goes to waste, into biodegradable plastic.
The aim is to make the process fully circular: at the end of their lives, the plastics could be ingested by more flies, which would then provide the new batch of raw material.
But how exactly does it work?
Black soldier flies are already an agricultural commodity, cultivated widely for animal feed because they’re an increasingly popular alternative protein to fish and soy meal.
Because they have good nutritional value from the food scraps they eat, it helps do away with organic waste.
Typically, however, only the larvae are harvested for feed and once the adults mate and breed, farmers discard them — though it’s the hard shells of the mature insects that caught the researchers’ attention.
This is because they contain chitin, a strong, fibrous substance that makes up the exoskeleton armour of the flies.
Using processes involving the application of ethanol, acid, and bleach, the team was able to extract and purify this non-toxic, sugar-based polymer from the bugs to create a powder that they then turned into polycarbonates or polyurethanes, which are usually made from fossil fuel-based chemicals.
‘We’re taking something that’s quite literally garbage and making something useful out of it,’ says Cassidy Tibbetts, a graduate student on Wooley’s team.
‘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,’ continues Wooley, explaining that because the bioplastics are biodegradable, they are likely ingestible by the flies themselves, giving new flies the nutritional sustenance to become the next plastics.
‘So the insects would not only be the source, but they would also then consume the discarded plastics.’