Turning insect waste into biodegradable  plastics

In a new study, scientists have unlocked the potential of using insect waste, particularly the discarded carcasses of adult black soldier flies, to produce chemicals essential for manufacturing biodegradable plastics. This eco-friendly venture offers a promising solution to the looming global plastic pollution crisis.

The innovative research, led by Dr. Karen Wooley and her team at Texas A&M University, will be presented at the American Chemical Society (ACS) Fall 2023 meeting. This event, held both virtually and in person from August 13 to 17, will host nearly 12,000 presentations covering a plethora of scientific subjects.

Focus of the study

“For two decades, we’ve sought ways to turn natural products – like glucose from sugar cane or trees – into degradable polymers that won’t persist in the environment. But these resources have competing demands in food, fuel, construction, and transportation,” said Dr. Wooley.

Seeking an alternative, Dr. Wooley collaborated with Dr. Jeffery Tomberlin who proposed utilizing insect waste. 

In particular. Dr. Tomberlin focused on the black soldier fly farming industry, a domain he’s been instrumental in advancing.

Making garbage useful 

These fly larvae are nutritionally rich, making them invaluable for animal feed and waste consumption. The adults, however, have a fleeting post-breeding life and are typically discarded. 

Dr. Tomberlin’s idea to leverage these otherwise wasted carcasses provided a sustainable raw material source for the research.

“We’re taking something that’s quite literally garbage and making something useful out of it,” said Cassidy Tibbetts, a graduate student that works in Dr. Wooley’s lab.

A novel approach 

In her investigations, Tibbetts identified chitin as a primary component in the discarded flies. Chitin, a biodegradable sugar-based polymer, is vital for the hardening of insect exoskeletons. 

Manufacturers traditionally source it from crustaceans like shrimp and crabs. However, Tibbetts’s method of chitin extraction from flies might present a cleaner and allergen-free alternative. 

Dr. Wooley highlighted the novelty of their approach, noting that her team seems to be the first to use chitin from adult flies.

Superabsorbent hydrogel

In the lab, Hongming Guo has been focusing on converting this chitin into chitosan, a related polymer. The processed chitosan is then fashioned into bioplastics, such as a remarkable superabsorbent hydrogel that was developed by Guo. 

This hydrogel can absorb 47 times its weight in water in mere minutes. Dr. Wooley envisions it as a solution to Texas’s alternating flood and drought challenges, stating that this hydrogel could aid in moisture retention in soils, simultaneously degrading to nourish crops.

A sustainable future

Looking ahead, the team plans to delve into breaking chitin into glucosamines, the fundamental sugar molecules, to produce bioplastics traditionally derived from petrochemicals. 

Moreover, the researchers aim to exploit other compounds found in black soldier flies, like proteins, DNA, and fatty acids, to create sustainable products.

Dr. Wooley envisions a sustainable loop where insects feed on discarded plastics, which are then harvested for components to produce new plastics. 

This approach not only aligns with the circular economy concept but also offers a novel way to combat the ongoing plastic pollution issue. With initiatives like these, there’s hope for a cleaner and more sustainable future.

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