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Scientists discover the secret to breaking down plastic: Beeswax-eating worms

By Erica Cirino

Federica Bertocchini is a developmental biologist at the University of Cantabria in Spain. Most days she can be found dressed in a white coat working on experiments in her lab. But in her spare time this scientist works in her backyard—wearing a protective suit, gloves and veil—tending to her bees.

Two years ago Bertocchini’s scientific work and beekeeping hobby collided into a major discovery. Like many beekeepers, Bertocchini must pluck pesky wax worms, a type of moth larvae that feed on beeswax and, if left to their own devices can munch through an entire hive. One day while de-worming her hives, she tossed the worms into an old grocery bag and left it outside. An hour later she picked up and inspected the bag and noticed small holes in the part where the worms were concentrated.

While Bertocchini is not a bug expert, she says her background in biochemistry led her to hypothesize that the worms were consuming the plastic bag, which was made of polyethylene—one of the most widely used types of plastics in the world.

“The characteristic chemical bond of polyethylene is also present in wax, although wax is made up of a different mix of molecules,” says Bertocchini.

Honey bees. Photo by PollyDot (Pixabay)
Honey bees. Photo by PollyDot (Pixabay)

Wax, like plastic, is a type of polymer, or substance made of a large number of the same type of molecule bonded together many times. Both wax and plastic are polymers held together with a string of linked carbon atoms, with other atoms attached to the sides. Because wax worms eat beeswax, Bertocchini thought maybe they contain some sort of specialized enzyme to break down its chemical bonds—and that same chemical may be capable of breaking down the bonds in plastic.

To find out, Bertocchini, with her University of Cantabria colleagues Paolo Bombelli and Christopher Howe, headed to their lab with worms and plastic. They placed 100 worms on samples of a polyethylene bag, watched and waited. They found that the worms created an average of 2.2 holes per hour in the plastic, and overnight consumed 92 milligrams of the bag. These statistics suggest it would take 100 worms one month to break down the average 5.5-gram polyethylene grocery bag. Their paper detailing this experiment was published this week in the journal Current Biology.

Trash, mostly plastic bags, in Karachi, Pakistan. Photo by Zainub Razvi
Trash, mostly plastic bags, in Karachi, Pakistan. Photo by Zainub Razvi (Flickr)

Polyethylene is the simplest of all commercially produced plastic polymers. Because all plastics have slightly different chemical makeups, could wax worms be capable of breaking down other varieties of plastic, such as polyvinyl chloride (used to make products like clear food packaging and shampoo bottles), polystyrene (used to make food trays and egg cartons) or polypropylene (used to make yogurt tubs and condiment bottles)?

“We do not know that yet, that is an interesting question, definitely worth studying,” says Bertocchini.

The scientists found it is indeed some sort of special chemical on or inside worms that breaks down the polyethylene, and is not just the chewing action of the worms’ jaws that break the plastic down. They determined this by spreading mashed-up dead worms on the plastic and watching the plastic break down before their eyes. It could be an enzyme inside of the worms, or perhaps a certain kind of bacteria in or on the worms’ bodies, that breaks down the plastic—more research is needed to determine which. While the precise aspect of the worms’ biology responsible for breaking down polyethylene remains unknown, the scientists say it converted the plastic into ethylene glycol, a type of moderately toxic chemical used in antifreeze.

Waxworm. Photo by USGS Bee Inventory and Monitoring Lab (Flickr)
Waxworm. Photo by USGS Bee Inventory and Monitoring Lab (Flickr)

Despite the challenges of degrading plastic on a large scale, Bertocchini says the knowledge that wax worms are capable of breaking down plastic could prove extremely valuable in the future. Each year the world produces about 300 million tons of plastic, with 8 million tons of that plastic entering the oceans and millions of tons more being littered on land or dumped into landfills. People wouldn’t sprinkle wax worms over piles of polyethylene, says Bertocchini, but apply the special plastic-degrading chemicals the worms contain.

“The idea would be to isolate the molecules responsible for the biodegradation, produce them in large industrial scale, and then apply that tool to biodegrade polyethylene,” Bertocchini says.

Dolphin caught on plastic bag in Fernando de Noronha, off Brazil's coast. Photo by Jedimentat44 (Flickr)
Dolphin playing with plastic bag in Fernando de Noronha, off Brazil’s coast. Photo by Jedimentat44 (Flickr)

Whether or not wax-worm solvents will be developed and mass-produced in the future is yet to be seen. Perhaps it could help get rid of some of the world’s plastic. But, experts say, getting rid of plastic is only one aspect of remediating the world’s plastic problem. The best way to cut down on the pollution is to stop producing and using plastic products.

Comments

  1. Chan Paula
    Philippines
    July 15, 12:29 am

    this is great but we should do a further research about their waste, whether the waste will have harmful chemical in it or not. Another problem is 100 worm, one month and only 5.5 gram the number is too small for our 25 million per month , so instead of letting them eat how bout lets find the enzymes that digest plastic and mass produce it.

  2. Harrison Oates
    Australia
    July 14, 7:45 pm

    Thankyou, Im writing a paper on plastic bags at the moment

  3. Nitai
    India
    May 3, 12:35 am

    I work with food and plastic waste that comes as part of the packaging. It is criminal, to say the least, to have food waste & to top it wrapped in plastic. All options that i have sought are expensive and not sustainable for my work. This is an eye opener.

  4. NICHAN SROURIAN
    United States
    May 2, 11:40 pm

    We cannot get rid of termites that consume our houses.
    If worms start eating plastics, it will be the end of the world, because most of chemicals acids and explosives are stored in plastic containers.

  5. Ayee Go
    India
    May 2, 8:26 pm

    Plastic waste seems to be the #1 menace for the environment, especially in developing counties. This gives a huge hope. Wonderful!

  6. Cheryfa MacAulay Jamal
    Mississauga, Canada
    May 1, 9:04 pm

    I remember tiny holes in plastic bags from the bulk food store that I used for lentils in my kitchen cupboard. There are two kinds of tiny bugs which come into your cupboards, one skinny black one that lives in rice, and a tiny little brown round one that lives in spices. I can’t remember which ones used to love the lentils, I think it was the rice bugs. I used to restore my dried goods in fabulous stacking/matching containers, and huge matching lidded buckets for rice and flours, to protect everything from these bugs, but then discovered that the original bags they come in have some protective chemical in them, because even in the closed containers, the unseen eggs would hatch and I would get the bugs anyway. Now that I use the original packaging, and keep a few choice spices in the freezer, no more bugs.

    Anyway, I don’t know if these bugs (more probably their larvae, I suppose), would actually thrive on plastic as these worms do, but if they can, then there is another creature we could study to hopefully engineer for plastics cleanup.

  7. Colby Collin
    May 1, 10:54 am

    This helped so much, i’m writing a paper on plastic and this was just the article that I needed!

    first hehe

  8. Gabriel Pineiro
    April 30, 11:32 am

    Im a common environmetalist and it would be really cool to some how purchase these worms by the dozen for a home-based, plastic feeding ground. Is there an easy way to acquire them withkut cultivation feom an actual beehive?! Mother nature, once again, gives us a cure.