Plastic pollution is one of the biggest environmental problems of our time.
More than 400 million metric tons of plastic are produced globally every year, and much of it ends up as waste that lingers in landfills and oceans for decades.
Now, researchers at Monash University have developed a promising alternative: natural plastics made from food waste sugars.
These materials are biodegradable, compostable, and strong enough to replace petroleum-based plastics in everyday packaging.
The research, published in Microbial Cell Factories, focuses on a special class of biopolymers called polyhydroxyalkanoates (PHAs). PHAs are produced naturally by certain bacteria, which stockpile them as reserves inside their cells.
Scientists have long been interested in PHAs as an alternative to conventional plastics, but making them versatile and scalable has been a challenge.
In this new study, researchers fed food waste sugars to two soil-dwelling bacteria: Cupriavidus necator and Pseudomonas putida.
With the right balance of salts, nutrients, and trace elements, the microbes “fattened up” and began storing natural plastics inside their cells.
The team then extracted the plastic, processed it with solvents, and cast it into ultrathin films only 20 microns thick—about one-fifth the thickness of a human hair.
When tested, the films showed properties comparable to conventional plastics. They could stretch, resist tearing, and be molded into other shapes or solids.
By blending plastics produced by the two bacterial strains, the scientists could fine-tune important properties such as stiffness, flexibility, and melting point.
For example, the plastic made by C. necator was stiffer, while the version from P. putida was softer and more elastic. Together, they created films that balance strength and flexibility, making them suitable for a wide range of uses.
“This research demonstrates how food waste can be transformed into sustainable, compostable ultrathin films with tunable properties,” said lead author Edward Attenborough.
“By tailoring these natural plastics for different uses, we’re opening the door to sustainable alternatives in packaging, especially where they can be composted along with food or agricultural waste.”
The versatility of PHAs makes them especially promising for applications such as food packaging, agricultural films like silage wrap, and even medical materials. Because the plastics can be composted, they could dramatically cut down on single-use plastic waste, particularly in industries where packaging is short-lived.
The Monash team, led by Attenborough and Dr. Leonie van ’t Hag, is now working with industry partners including Enzide and Great Wrap through the ARC RECARB and VAP hubs. Together, they aim to bring these biodegradable films closer to commercial use, from packaging to medical solutions.
The study also builds on earlier research showing that PHAs could be used for sustainable drug delivery systems, adding to their wide potential.
By transforming food waste into useful, compostable plastics, the researchers hope to create a circular system that reduces waste and provides eco-friendly alternatives to the plastics we use every day.
