The bunches of bananas that we buy in stores grow off of a central trunk-like structure, known as the pseudostem. And while that part of the plant is typically discarded during harvesting, it may soon find use in a plastic that biodegrades and is fully recyclable.
According to Australia’s University of New South Wales (UNSW), the growing of bananas is a particularly wasteful form of agriculture, with only 12 percent of the plant actually being used. The pseudostem makes up much of the rest, and while it can be composted or used in the production of textiles, it’s usually just thrown away.
In order to bring new value to that waste, a UNSW team led by Assoc. Prof. Jayashree Arcot and Prof. Martina Stenzel developed an experimental new recycling process.
It begins with the pseudostem being chopped up into pieces, those pieces then being dried in an oven at a low temperature, and then milled into a fine powder. That powder is subsequently washed via a soft chemical treatment. This step isolates a material called nanocellulose – which is made up of tiny cellulose fibers – from the rest of the powder. It is from that nanocellulose that sheets of the plastic are made.