Biology

The hungry gut bacteria that enable waxworms to live on plastic waste

The hungry gut bacteria that e...
Scientists have found that gut bacteria in waxworms is a key driver of their appetite for plastic
Scientists have found that gut bacteria in waxworms is a key driver of their appetite for plastic
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Scientists have found that gut bacteria in waxworms is a key driver of their appetite for plastic
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Scientists have found that gut bacteria in waxworms is a key driver of their appetite for plastic
A waxworm nibbles away at a plastic bag
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A waxworm nibbles away at a plastic bag
Bryan Cassone (from left to right), Harald Grove, Christophe LeMoine and Sachi Villanueva are members of a research team at Brandon Univeristy investigating how waxworms are able to survive on a diet of plastic
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Bryan Cassone (from left to right), Harald Grove, Christophe LeMoine and Sachi Villanueva are members of a research team at Brandon Univeristy investigating how waxworms are able to survive on a diet of plastic
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Plastic pollution is a monumental issue and one that isn’t going away anytime soon, but researchers are opening up new possibilities around how we could chip away at the problem. Scientists working in this area at Canada’s Brandon University have made an exciting discovery, zeroing in on the mechanisms that enable a common species of caterpillar to survive on a diet of plastic alone.

In recent years, scientists have identified a number of organisms with an ability to eat away at common plastics. These include engineered enzymes, mealworms with an appetite for Styrofoam and a type of bacterium with an ability to break down PET plastics in a relatively short space of time.

Waxworms are another exciting example. These are the caterpillar larvae of the wax moth and act as destructive parasites in beehives by feeding on the beeswax, much to the disdain of beekeepers. But earlier research has found that these critters also have quite an appetite for plastic, with an ability to chew through it, digest it, and turn it into ethylene glycol, a type of alcohol.

Led by Dr. Christophe LeMoine and Dr. Bryan Cassone, researchers at Brandon University’s Department of Biology have been investigating the mechanisms underlying this unique behavior. Their work reveals that the plastic-devouring abilities of the waxworm can be tied to a species of gut bacteria, which they managed to isolate and prove actually thrive on a diet of plastics.

In the team’s experiments, the waxworms were able to survive purely on a diet of polyethylene, the type of plastic used in shopping bags, disposable drinking caps, soda bottles and other everyday items. The creatures have such a ravenous appetite for it, that 60 of them were able to devour more than 30 sq cm (4.7 sq in) of a plastic bag in less than a week.

A waxworm nibbles away at a plastic bag
A waxworm nibbles away at a plastic bag

The team found that a key factor in this is a species of bacteria contained in the gut of the waxworms that biodegrade polyethlyene. These bacteria were able to be kept alive for more than a year, relying only on plastic for their nutrients. While the waxworms can degrade plastic on their own, and so too can the bacteria when isolated, they do a much better job of it when working in tandem.

“Plastic-eating bacteria are known, but in isolation they degrade plastics at a very slow rate,” Dr. LeMoine said. “Likewise, when we treated the caterpillars with antibiotics to reduce their gut bacteria, they were not able to degrade the plastic as easily. So it seems that there is a synergy between the bacteria and their waxworm hosts that accelerates plastic degradation.”

When the scientists fed the waxworms a diet of 100 percent plastic, it actually increased the microbes in their guts compared to waxworms on a regular diet. As such, they have dubbed them “plastivores,” and will continue to study the relationship between the worms and their gut bacteria, looking to learn how they might maximize their ability to degrade plastic waste.

“Worms that eat our plastic waste and turn it into alcohol sounds too good to be true. And in a way it is,” said Dr. Cassone. “The problem of plastic pollution is too large to simply throw worms at. But if we can better understand how the bacteria works together with the worm and what kind of conditions cause it to flourish, perhaps this information can be used to design better tools to eliminate plastics and microplastics from our environment.”

The team has published its findings in the journal Proceedings of the Royal Society B.

Source: Brandon University

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8 comments
Aross
Besides the alcohol what other waste is produced by these bugs? How harmful is that to the environment. That is a question that still needs to be answered.
Catweazle
Lots and lots of scope for unintended consequences here, check out Michael Crichton's excellent "The Andromeda Strain".
BlueOak
“The hungry gut bacteria that enable waxworms to live on plastic waste”.... What a relief - this isn’t about the human gut. ‘Lots of stories lately about the gut and heath, so that headline is a setup for misinterpretation! ;-)
bwana4swahili
Could be a godsend for plastic recycling. Hope it goes somewhere considering the amount of plastic going into landfills and piles all over the country!
mediabeing
This is how we get giant car-eating caterpillars!
GOllieOlwagen
Hope everyone realizes that these critters (the worms, that is) also eat bees wax, and if you should ever increase their numbers in open rubbish dumps to devour the plastics in unison with the gut bacteria, you can create a world-wide problem. There could also be a massive killing-off of bees (all needing to start their lyfe-cycle inside wax cells) and that would mean they couldn't pollinate many food plants that depended on them to produce their fruits. Right?
Biscuitcutter
The findings of this research are interesting and of potential great value to our environment, but there may be an anomaly worth exploring. I am a beekeeper and I have witnessed first hand the destruction these critters can cause to a beehive. They tunnel through the wax and even the wood framework in a hive and completely destroy it. But there is a type of beehive "foundation" that is plastic (I don't know what kind) molded in the form of honeycomb then coated with a thin coat of beeswax so it is attractive to the bees. When wax worms attack this type of honeycomb, they eat all the beeswax (and brood and honey and wood) they can find but leave the plastic honeycomb foundation intact. So, is there a type of plastic they won't eat? Or do they get their fill of more delectable items and move on?
Vernon Miles Kerr
But if we used waxworms on the Great Pacific Gyre, what unimaginable flying pestilence would spring from their cocoons?