Flies a buzz in plastics debate

Finnish scientists have discovered a way of using dead flies to produce bioplastics that unlike conventional plastics quickly break down in the environment.

Researchers say this represents a significant step towards more sustainable and eco-friendly materials.

The project's principal investigator, Karen Wooley, said her team had spent two decades developing methods to convert natural products, like glucose from sugar cane or trees, into degradable plastics that do not linger in the environment.

“However, we were using materials that are also sources of food, fuel, and are needed in other essential industries. We wanted something that nobody else wanted,” Dr Wooley said.

Her colleague, Jeffery Tomberlin, suggested exploring waste products from farming black soldier flies – a rapidly growing industry in which he has been closely involved.

“Black soldier fly larvae contain a wealth of proteins and nutritious compounds, making them valuable for animal feed and waste consumption,” Dr Tomberlin said.

“However the adult flies have a short lifespan after breeding and are usually discarded.”

Dr Wooley set graduate student Cassidy Tibbetts to work on the project. She discovered that the adult fly carcasses contained chitin, a biodegradable polymer derived from sugar that strengthens the exoskeleton of insects and crustaceans.

Ms Tibbetts developed an extraction process that produced chitin powder with improved purity and characteristics.

She worked with another graduate student, Hongming Guo on a chemical process that converted purified chitin into chitosan, which in this form can be transformed into useful bioplastics, such as superabsorbent hydrogels, with the ability to absorb vast amounts of water.

Dr Wooley said this technology could have applications in cropland soil, capturing floodwater and releasing it slowly during droughts.

“Furthermore, because the hydrogel is biodegradable, it can gradually release nutrients to nourish crops,” she said.

Her team is now working on turning chitin from the flies into monomeric glucosamines, small sugar molecules that can be used to produce traditional bioplastics like polycarbonates and polyurethanes.

“We are also looking at the diverse array of compounds found in black soldier flies, including proteins, DNA, fatty acids, lipids, and vitamins, to create sustainable and degradable materials that contribute to reducing plastic pollution,” Dr Wooley said.

“In the future I can see a circular economy where insects consume waste plastic as a food source, and their components are harvested to create new plastics.

“This is the future where nature's processes drive innovation towards a greener world.”