by Editor, Esther Chan.
Australian teenager, Angeline Arora, has identified prawns as a new source for bioplastics which can decompose in a landfill over just 33 days.
Bioplastics are plastic materials produced from biomass sources like corn starch, woodchips and recycled food waste. Arora’s project was inspired by a trip to the supermarket when she asked the cashier why they were charged for plastic bags.
After learning that it was to deter people from using plastic bags to save the environment, she thought “there has to be a way where humans can have their needs met and use plastic bags, but also not damage the environment.”
The encounter turned her attention to experiment with organic waste like banana peels, but no to avail. She told National Geographic that “I looked at prawns and thought what makes their shells look like plastic? Maybe I can take that out and use it someway and bind it to make a plastic-like material.”
Prawns contain a carbohydrate called chitin, and crustacean shells like those of prawns contain up to 20-30% of it. Crab shells also contain a similar percentage of chitin, with lobsters containing up to 40% of the carbohydrate.
She harvested the chitin and chemically converted it into chitosan and combined it with fibroin, which is a protein found in silk cocoons. The result is a sophisticated bioplastic that decomposes within 33 days.
Chitin extraction can be achieved mainly by two methods, either chemically or biologically. The chemical method involves an alkali treatment and organic solvent treatment, which can be toxic and degradative. This makes the resulting chitin unsuitable for medicinal use and increases the cost of processing food waste.
The biological method however is an advanced and new technique for chitin extraction. This method involves the use of enzymes and achieves a higher chitin yield. Overall it is an affordable and eco-friendly one that possesses environmental advantages over the chemical method.
Her invention won her the Innovator to Market Award in the 2018 BHP Billiton Foundation Science and Engineering Fair. She also placed 4th in the world and won a comprehensive scholarship to a prestigious university in the U.S at the Intel International Science and Engineering Fair.
Chemical engineer Ramani Narayan from Michigan State University told National Geographic that “The argument for bioplastics is the inherent value of reducing the carbon footprint.”
About eight percent of the world’s oil is used to make plastic, and proponents of bioplastic often tout a reduction in its use as a significant advantage. The argument rests on the basis that if a plastic item releases carbon into the atmosphere as it degrades, bioplastics will add less carbon comparatively. Conventional plastics would release carbon previously trapped underground in the form of oil.
However, a 2011 study from the University of Pittsburgh revealed that there are other environmental considerations associated with growing crops for bioplastics. Using the corn crop for plastic instead of food purposes is at the centre of a debate over how resources should be stewarded in light of food scarcity.
Nevertheless, Arora’s innovative bioplastic technology marks a change for packaging in the efforts towards carbon emission reduction.