Flies could soon be turned into degradable plastics, according to new research.
American scientists say the concept is close to reality after they isolated and purified insect-derived chemicals.
Project principal investigator Professor Karen Wooley 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.”
Wooley began searching for alternative sources that wouldn’t have competing applications.
Her colleague Professor Jeffery Tomberlin suggested she could use waste products left over from farming black soldier flies, an expanding industry that he has been helping to develop.
The larvae of those flies contain several proteins and other nutritious compounds, so the immature insects are increasingly being raised for animal feed and to consume wastes.
But the adults have a short life span after their breeding days are over and are then discarded.
At Tomberlin’s suggestion, those adult carcasses became the new starting material for Wooley’s team.
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.”
When Tibbetts examined the dead flies, she determined that chitin is a major component. She said the non-toxic, biodegradable, sugar-based polymer strengthens the shell, or exoskeleton, of insects and crustaceans.
Manufacturers already extract chitin from shrimp and crab shells for various applications.
Tibbetts has been applying similar techniques using ethanol rinses, acidic demineralization, basic deproteinization and bleach decolorization to extract and purify it from the insect carcasses.
She says her fly-sourced chitin powder is probably purer, since it lacks the yellowish colour and clumpy texture of the traditional product.
She also said that obtaining chitin from flies could avoid possible concerns over some seafood allergies.
Other researchers isolate chitin or proteins from fly larvae, but Wooley says her team is the first that she knows of to use chitin from discarded adult flies, which – unlike the larvae – aren’t used for feed.
While Tibbetts continues to refine her extraction techniques, Hongming Guo, another graduate student in Wooley’s lab, has been converting the purified fly chitin into a similar polymer known as chitosan.
The Texas team has produced a hydrogel that can absorb 47 times its weight in water in just one minute.
They say the product could potentially be used in cropland soil to capture floodwater and then slowly release moisture during subsequent droughts,
Wooley said: “Here in Texas, we’re constantly either in a flood or drought situation.
“I’ve been trying to think of how we can make a superabsorbent hydrogel that could address this.”
Because the hydrogel is biodegradable, she says it should gradually release its molecular components as nutrients for crops.
Her team has started a project to break down chitin into its monomeric glucosamines.
Wooley says the small sugar molecules will then be used to make bioplastics, such as polycarbonates or polyurethanes, which are traditionally made from petrochemicals.
She said that black soldier flies also contain many other useful compounds that the group plans to use as starting materials – including proteins, DNA, fatty acids, lipids and vitamins.
Wooley explained that the products made from the chemical building blocks are intended to degrade or digest when they’re discarded, so they won’t contribute to the current plastic pollution problem.
She added: “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.”
The findings are due to be presented at a meeting of the American Chemical Society in San Francisco.
Produced in association with SWNS Talker
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