Caterpillars eating through plastic bag… bacterium that use toxic plastics for food… Mushrooms eating through plastics… Sounds like something from a science fiction film, right? And yet, each of these have hit the headlines, with stories of the plastic-eating bacterium only coming to light in the past couple of weeks.
We wanted to explore these weird and wonderful discoveries a little more, and find out whether they have the potential to benefit our fight against plastic. We’ve taken a closer look, to see what the scientists are saying.
Is it really true that bacteria can eat plastic?
It would seem so – the recent discovery of a bacterium that feeds on toxic plastic was made at a waste dump site. It has now been written about in the journal Frontiers in Microbiology, the leading journal in its field. The bacterial strain is able to break down polyurethane, one of the most problematic types of plastic that is rarely recycled.
A closer look at plastic-eating bacteria
Name: Pseudomonas sp. TDA1.
When it was discovered: It was first written about in Frontiers in Microbiology on 27 March 2020.
Abilities: The revolutionary Pseudomonas strain appears to be capable of breaking down toxic polyurethane plastic, and using it as food during the process as well. Polyurethane is produced for use in items from nappies and sponges, to sports shoes and building insulation, but items made from the plastic are too difficult to recycle and usually end up in landfill. The carcinogenic chemicals that are released when breaking it down would kill most bacteria, but not Pseudomonas. Scientists fed it the key chemical components of polyurethane in a laboratory, and the bacteria used them as a sole source of carbon, nitrogen and energy.
Limitations: There’s lots of work to be done before Pseudomonas bacteria could be used in the treatment of bulk plastic waste. A scientist working on the research into it gave an estimate of 10 years before it might be used to treat waste on a large scale – he emphasised the importance of reducing plastic usage in the meantime.
A closer look at plastic-munching worms
Name: Galleria mellonella, or greater wax moth larvae
When was it discovered they ate plastic? Wax moth larvae first hit headlines in 2017 when they ate through a plastic bag.
Abilities: The Spanish National Research Council and Cambridge University looked into the claims further, and found in lab tests that 100 worms could eat 92mg of polyethylene – the most common type of plastic – in just 12 hours. This led scientists to speculate on the possibility of using the worms to manage plastic waste and prevent it mounting up.
Limitations: There’s a dark side to the idea of breeding billions of these creatures to eat through our plastic waste. Galleria mellonella get their name from their main source of food, and they favour the type of wax that bees use when making honeycomb. Breeding high numbers of these worms could see them devastating bee colonies – and that’s not to mention the difficulties involved in producing enough of them to make a dent in plastic waste in the first place.
A closer look at plastic-consuming mushrooms
Name: Pestalotiopsis microspora, a rare type of Amozonian mushroom
When was it discovered they ate plastic? Yale students made headlines in 2011 when they discovered the fungus in Ecuador.
Abilities: It was discovered that Pestalotiopsis microspore have the ability to digest and break down polyurethane plastic. A few years later, the fungi mutarium was created, which used Pleurotus ostreatus (oyster mushrooms) and Schizophyllum commune (split gill mushrooms) to fully degrade small pieces of plastic. Since then, one team alone has discovered around 50 more species of mushroom that can degrade specific types of plastic.
Limitations: Funding for research is a major barrier, and fungi are much more difficult to use in bulk and harness for industrial use than bacteria.
A realistic solution?
Let’s get to the crux of the matter: sadly, plastic-eating worms, mushrooms and bacteria are very unlikely to save the planet any time soon. However, the newly-discovered Pseudomonas bacterium is certainly the most promising of the three and will no doubt be carefully researched – perhaps it could have a place in the waste management systems of the future.
Reducing plastic waste – taking realistic steps
Advances in science are happening all the time, and who knows, the next might discovery might just help save the planet from out mountains of plastic waste. But we can’t rest on our laurels and wait for a miracle cure. It’s essential we all take responsibility for our own waste and endeavour to reduce plastic usage wherever possible. We have some top tips for reducing plastic usage that you can follow in your everyday life – they’re super simple, and whilst you might be limited in where you can shop during the coronavirus pandemic, there’s still plenty of food for thought. We’re only ever going to reduce plastic pollution if we all work together and make changes to our lives. Saving the planet starts at home – we can’t leave it up to the scientists.