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.

A sample of the banana-nanocellulose plastic University of New South Wales



The finished product has a consistency not unlike that of the parchment paper used in baking, and could potentially be used in products such as shopping bags and food packaging. It can be fully recycled up to three times without any loss in quality, and when it is discarded and placed in the soil, it breaks down organically. Additionally, lab tests indicate that the material doesn't leach any harmful compounds into food.

The scientists are now seeking industry partners who are interested in scaling the process up to commercial production levels, and making it as cost-effective as possible.

Source: University of New South Wales