Deep in the forest, a white-rot fungus quietly devours fallen trees. It produces enzymes so powerful they can dismantle lignin — one of the toughest natural polymers on Earth. Now, that same trick has inspired a breakthrough that could transform how we deal with plastic waste.
A team led by Dr Yimin Wu and PhD student Wei Wei at the University of Waterloo in Canada has created a synthetic catalyst that mimics the fungus's chemistry. Using sunlight, it breaks down everyday plastics — carrier bags, drinks bottles, food containers, even PVC pipes — and converts them into acetic acid, the chemical that gives vinegar its tang.
From forest floor to laboratory
The white-rot fungus (Phanerochaete chrysosporium) breaks down wood using enzymes that generate highly reactive molecules capable of tearing apart complex carbon structures. The Waterloo team wondered: could a synthetic material do the same thing to plastic?
Their answer is an iron-doped carbon nitride — a light-absorbing semiconductor studded with individual iron atoms, each one acting like a tiny enzyme. Scientists call it a "single-atom catalyst." Each iron atom is isolated and precisely positioned, maximising its ability to drive chemical reactions.
A two-step trick
The process is elegantly simple in concept. When sunlight hits the catalyst in a water solution containing hydrogen peroxide, the iron atoms generate powerful reactive molecules called hydroxyl radicals. These radicals attack the long carbon chains in plastics, chopping them into ever-smaller fragments until carbon dioxide forms.
Here's the clever part: instead of letting that CO₂ escape, the same catalyst uses sunlight to convert it into acetic acid. The carbon in your old plastic bag is dismantled and then reassembled into something valuable — all in one system, at room temperature and normal pressure.
That's a stark contrast to conventional chemical recycling, which typically requires heating plastics to several hundred degrees Celsius.
Why vinegar matters
Acetic acid might sound humble, but it's an industrial heavyweight. Beyond salad dressings, it's used to make adhesives, coatings, solvents, synthetic fibres, and pharmaceuticals. Global demand runs into millions of tonnes each year, worth billions of dollars. Most of it is currently produced using an energy-intensive process involving methanol and carbon monoxide at high temperatures.
Making acetic acid from waste plastic instead offers a genuinely circular pathway — reusing carbon that's already been extracted rather than pulling more from the ground.
It works on the messy stuff, too
One of the most promising findings is that the catalyst handles mixed plastics. Real-world waste is rarely neatly sorted, and many recycling technologies struggle with contamination. The Waterloo system converted polyethylene, polypropylene, PET, and PVC — individually and in mixtures. PVC, often considered one of the most problematic plastics, actually performed best. The chlorine released during its breakdown appears to generate additional reactive molecules, speeding things up.
The iron atoms remained stable after repeated use, an important factor for any technology hoping to scale up.
The road ahead
The research is still at laboratory scale. Challenges remain around reactor design, light penetration, and handling the additives found in commercial plastics. The system also requires hydrogen peroxide, and sourcing that sustainably at scale will need further work.
But the fundamental proof of concept is striking. "This method allows abundant and free solar energy to break down plastic pollution without adding extra carbon dioxide to the atmosphere," said Dr Wu.
Plastic is not going away — but perhaps it doesn't have to be waste. If sunlight and a fungus-inspired catalyst can turn yesterday's packaging into tomorrow's industrial chemicals, the story of plastic might just get a second chapter.
