In the face of the growing global crisis due to plastic pollution, a team from Monash University in Melbourne (Australia) has managed to transform food waste into ultra-thin and compostable bioplastics, paving a promising path towards a more efficient and less polluting circular economy.
What are PHAs and why do they matter?
Biopolymers produced by bacteria that mimic the properties of plastic but are biodegradable.
Polyhydroxyalkanoates (PHA) are bioplastics generated by bacteria from renewable sugars, such as glucose and fructose extracted from food waste. According to the journal Microbial Cell Factories, these materials are:
- Non-toxic and home compostable
- Biodegradable in marine environments
- Adaptable to replace single-use plastics
Soil bacteria as biopolymer factories
Cupriavidus necator and Pseudomonas putida transform waste into functional materials.
The team led by Edward Attenborough and Dr. Leonie van ‘t Hag used two soil bacteria:
- C. necator H16: produced up to 60% PHB with fructose
- P. putida KT2440: generated more flexible mcl-PHA, although in smaller proportions
Both species were fed with mixtures of sugars, salts, and nutrients, accumulating PHA inside them, which was then extracted and converted into 20-micron thick films.
Physical properties: rigidity, flexibility, and custom design
Mixing PHB and mcl-PHA allows adjusting the strength and elasticity of the bioplastics.
- PHB: rigid, crystalline, high melting point (172–175°C), low elongation (2–8%)
- mcl-PHA: amorphous, low melting point (42–43°C), high elongation (300–500%)
The mixtures (from 100:0 to 20:80) allowed modulating crystallinity, adhesiveness, and thermal behavior, although in thin sheets the flexibility was limited by the biphasic structure.
“This research demonstrates how food waste can be transformed into sustainable films with adjustable properties,” Attenborough noted.
Applications and commercial projection
Food packaging, medical films, and agricultural uses with domestic compostability.
The developed bioplastics have potential for:
- Compostable food packaging
- Biodegradable medical films
- Agricultural applications that integrate into the organic cycle
Monash University collaborates with companies like Enzide and Great Wrap, through the ARC RECARB and VAP hubs, to scale up production and validate the technology in the market.
Conventional plastics: a persistent problem
Uncontrolled production, low recycling rate, and severe environmental and health impacts.
- More than 400 million tons of plastic per year
- Less than 10% is properly recycled
- Microplastics and nanoplastics detected in water, food, and human bodies
- 85% of marine waste is plastic
- Up to 1.5 trillion dollars in annual health losses
Science for a circular transition
Compostable bioplastics as a response to pollution and climate change.
This advancement demonstrates that it is possible to revalue food waste and convert it into functional and sustainable materials, capable of reincorporating into the organic cycle and reducing the environmental footprint of synthetic plastics.
