Imma Perfetto
Cosmos science journalist
A fruit or vegetable punnet that biodegrades completely in soil, fresh water, the ocean, and in compost has been developed in Queensland, Australia.
Mass-produced food packaging, such as the hard plastic punnets used to box berries, tomatoes, and other fresh produce at the grocery store, are in need of a sustainable upgrade.
Researchers in Queensland have developed just that. Their “bio composite” commercial alternative to petrol-based plastics is made by blending bacteria-produced biodegradable polyester – known as polyhydroxyalkanoates (PHAs) – with wood fibres from radiata pine sawdust.
PHAs are naturally occurring carbon and energy storage compounds found in various bacteria and are considered a promising alternative to petrol-based plastics because they biodegrade in a diverse range of natural environments without generating contamination or persistent nanoparticles.
“This is a new material that carries all the sustainability benefits of a bio-sourced product while having the same properties as mass-produced plastic packaging and containers,” says PhD candidate Vincent Mathel, who produced the material with Dr Luigi Vandi at UQ’s School of Mechanical and Mining Engineering.
“It was also important to make a bio composite that maximises Australian resources to have the added, environmental benefit that it does not need to be imported.”
The team worked with Australian biotech Uluu and injection moulding firm SDI Plastics to manufacture the 200 strawberry punnets using cost-effective, conventional industrial processing techniques.
“Punnets are pretty bad from a sustainability perspective, but they are the only way to effectively ship and sell strawberries without ruining the fruit,” says Vandi.
“We’ve shown we can make a product that could potentially replace the 580 million or so plastic punnets every year.”
Packaging is the greatest source of global plastic waste, with 146 million tonnes produced in 2015 of which 141 million tonnes went unrecycled (96.6%).
Mathel believes the bio composite could also be used for a range of food packaging and other rigid plastic applications.
“The ultimate goal is to phase out petrol-based plastics,” Mathel says.
“Bioplastics will play a crucial role as a solution when plastics are unavoidable, especially for short-term applications.”
The research is presented in a paper published in Composites Part A: Applied Science and Manufacturing.
