Plastic Eating Fungi

Background

Plastic pollution is a huge issue across the globe; plastic pollution is already taking its toll on the earth as there was microplastics found in the oceans and clouds a few years ago, the main plastic found is polyethylene terephthalate and this takes ages to break down. There is a number of different household items and food containers that use PET plastic. The reason why it's so personal to me and my partner is because we constantly see that same type of plastic littered around where we live. It will take centuries for it to finally break down into nature. The same plastics we waste for one time use will outlive us all.

Inspiration

Our inspiration for this project was the amount of garbage that pollutions this earth. We see it every day, on the sidewalks, on the streets, on the roads. Yet we had grown so used to it. That's not how it's supposed to be. I used to be terrified of climate change, so we're very happy to study a way we could help the globe, even if it starts out as small as this.

Can Blue Oyster Mushrooms (Pleurotus ostreatus) break down or reduce the mass of PET plastic under controlled conditions?

The short answer for this question is yes, but only under controlled conditions unfortunately. This method can only work if it's watched and misted daily and in the right season. Though even with these limitations, I think this could save the planet

Materials

Blue Oyster Mushroom (Pleurotus Ostreatus)

PET plastic (cut from clean plastic bottles)

Scale

Mushroom growing kit

Spray bottle with distilled water

Logbook

Camera

Procedure

Cut PET plastic bottles into equal sized pieces. Wash and dry them thoroughly.

Measure and record initial mass of PET plastic pieces using a scale.

Prepare the mushroom growing kit according to instructions.

Insert the previously weighted PET plastic pieces into the mushroom growing kit.

Close containers and place them in a dark, warm environment.

Mist lightly with water as needed to maintain moisture.

Observe weekly for 4 to 6 weeks, writing down any visible growth and taking photos every day.

After experiment period, carefully remove the PET pieces.

Clean off any attached substrate gently.

Dry off plastic pieces completely.

Measure and record the final mass of each piece.

Compare the mass before and after experiment.

Research Background

To research more about plastic pollution and how my project could possibly solve the problem, we searched through various websites to read articles and research papers about this very topic. To help us understand what actual scientists are doing about this and how much plastic really does affect the globe. About 470 million tons of PET plastic were produced worldwide in 2025 alone. It won't go away for another hundreds of years. We hadn't known that before we started researching about this topic.

Results

At the start of the experiment, the mass of the PET plastic pieces was 2.00 grams.

After the experiment was complete, the mass of the PET plastic pieces were 1.50 grams.

Which means it overall lost 25% of its mass. Blue Oyster Mushrooms do truly break down PET plastic; the experiment was a success, and it only took us about 2 months to break down that much plastic. Just imagine how much more plastic can be broken down in years or so if the mushrooms can be used somehow to help with plastic pollution. We've chosen this method because it's simple. It's something we can do at home, and we just had to mist it 2 times a day, though I felt like I was doing something important to the world by nurturing it. The results of this were great, but we hope next time it will be even better.

Conclusion

The takeaway from all this is that this can actually help, this could save the world if only people studied this method of degrading plastic more. As I said before it only works in controlled conditions, so not everyone could do this yet. Though there are countless other mushrooms, fungi, and enzymes that break down plastic. This is just the one that we've tested. Most people weren't even aware that this could help with plastic pollution. That's why we are trying to make them aware, to see that there's a possible solution to this.

Improvements for Future Experiments

We could've made sure that the fungi had grown to its fullest potential using LED glow lights, using different types of plastics from different items, or being in a different season (spring or fall). We could also repeat the experiment many times with the same pieces of PET plastics to see if the mass can be completely decomposed. The final idea I have is that the mushroom growing kit had wood chips in it, so we really should've made sure it was just the plastic in there and not degrading because of anything else.

We'd like to express our gratitude to the people that helped us and encouraged us to keep going with this project. We'd like to thank Ebb and Flow Education for funding the supplies we used and paying for everything. We'd like to thank our families and friends for supporting us through this journey and lastly, we would like to thank the judges at the Manitoba Indigenous Science and Engineering Fair for making this opportunity possible.

Articles References

An engineered PET depolymerase to break down and recycle plastic bottles | Nature

A bacterium that degrades and assimilates poly(ethylene terephthalate) | Science

Scientists explore nature’s promise in combating plastic waste

Plastic Pollution Growing at Troubling Rate With Significant Environmental, Human Health Consequences | The Pew Charitable Trusts

Scientists discover microplastics are forming clouds in our atmosphere | The Independent

Researchers discover microplastics at all ocean depths | NSF - U.S. National Science Foundation

Plastic eating mushrooms: a viable solution to plastic decomposition | Environmental Center | University of Colorado Boulder

Plastic threat - Global Plastic Production in 2025 — Rising Volumes and a Mounting Environmental Crisis 15-10-2025 • Polyestertime

Videos References

How Mushroom Startups Use Fungi To Fight Waste | World Wide Waste | Business Insider - YouTube

Why the Plastic Pollution Problem Is So Much Worse Than You Think - YouTube

Why Does PLASTIC Last 'FOREVER'?

The smallest solution to one of our biggest problems - Tierney Thys & Christian Sardet - YouTube