2023-08-16 14:15:05
An eye-catching technique for creating biodegradable plastic from certain insects is closer to leaving the lab and entering the market than it might seem.
For about 20 years, Karen Wooley’s group, from Texas A&M University in the United States, has been developing methods to transform natural products, such as glucose obtained from sugar cane, into degradable and digestible polymers that do not persist in the body. around. But there’s a catch: Those natural products are made from resources that are also used for food, fuel, construction, and transportation. So this leads to a conflict of interest.
With this problem in mind, Wooley began to look for alternative sources of raw materials that did not cause this conflict. His colleague, Jeffery Tomberlin, suggested that waste products left over from the growing industry of commercial breeding of insects popularly known as “black soldier flies”, among other names, could be used.
The larvae of these insects contain a lot of protein and other nutritional compounds. And they feed on waste that would be difficult to recycle otherwise. The flourishing business mentioned consists of rearing larvae of this class to prepare from them highly nutritious food intended for feeding cattle.
However, the adults of that species of insect (Hermetia illucens) have a short life after their reproductive stage ends and there are always carcasses that must be removed from such “farms”. At Tomberlin’s suggestion, these adult carcasses were used as the new raw material for the system devised by Wooley’s team. “We are taking something that is literally garbage and turning it into something useful,” says Cassidy Tibbetts, of Texas A&M University and a member of the research team.
Insects of the Hermetia illucens species are a good source of chemicals with which to make bioplastics and other products. (Photo: Cassidy Tibbetts)
When Tibbetts examined the dead insects, he determined that chitin is an important component. This biodegradable and non-toxic sugar-based polymer strengthens the exoskeleton of insects and crustaceans. There are already many companies extracting chitin from the shells of crabs and other crustaceans for various applications. Tibbetts has been applying similar techniques, including ethanol rinses, acid demineralization, basic deproteinization, and bleach decolorization, to extract chitin from insect carcasses and purify it. However, everything indicates that the chitin powder produced from Hermetia illucens insects is purer. In addition, obtaining chitin from them instead of from crustaceans, could avoid risks in people allergic to shellfish.
While Tibbetts continues to refine his extraction techniques, Hongming Guo of Wooley’s lab has been converting purified black soldier fly chitin into a similar polymer known as chitosan. And, through a special chemical process, he creates bioplastics and other products from chitosan.
Among those other products, it is worth highlighting a hydrogel that can absorb 47 times its weight in water in just one minute. This product could perhaps be used on agricultural soils to capture water discharged by flooding and then slowly release it, something that would be helpful in dry seasons. The biodegradability of the hydrogel would also allow it to do things beyond the reach of traditional agricultural techniques, such as gradually releasing nutrients to crops.
This study is presented publicly at the congress that the ACS (American Chemical Society) celebrates these days in San Francisco, California, United States. The title of the study is “Harvesting of building blocks from insect feedstocks for transformation into carbohydrate-derived superabsorbent hydrogels”. (Source: NCYT from Amazings)
#Biodegradable #plastic #insects