Why do waxworms and bacteria love eating plastic? Brandon University research aims to find out
Researchers at Manitoba school wanted to dig deeper after discovery of plastic-eating worms in 2017
Researchers at Brandon University say throwing a bunch of tiny plastic-eating worms at the world's pollution problem won't solve it, but hope it could one day offer a little bit a help thanks to a type of bacteria found within the worm.
A team at the southwestern Manitoba university, located about 200 kilometres west of Winnipeg, published their findings on waxworms in Proceedings of the Royal Society B, a prestigious journal dedicated to biology, this month.
They set out to understand why the caterpillar larvae, that are typically found in bee colonies and feed on beeswax, can also survive on a diet of polyethylene — a type of plastic.
The researchers were able to home in on a species of intestinal bacteria in the worms that was able to survive on plastic — like the kind used in shopping bags and other consumer products — for more than a year as its only source of nutrients.
"It's been known for a while that some bacteria and some fungi can biodegrade some plastic, but it's very slow," said Christophe LeMoine, chair of the university's Department of Biology. "Here [with the waxworms] what's really phenomenal is that it can happen over, like, 24 hours … which is quite fascinating when you think about it."
LeMoine, along with an associate professor Bryan Cassone and a group of students, studied the bugs and the bacteria and found they work better together.
"Plastic-eating bacteria are known, but in isolation they degrade plastics at a very slow rate," 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."
It's not the first time the species has been studied for this type of application and LeMoine said he and the group at Brandon University hoped to build off of research done in Europe almost three years ago.
In research published in Current Biology in 2017, lead author Paolo Bombelli said a similar discovery was made by accident. His colleague Frederica Bertocchini, an amateur beekeeper (and a co-author of the paper), found holes in the plastic bags where she had placed the waxworms she had removed from her beehives.
After further study, they discovered it was the waxworms creating holes in the bags.
'Plastivores'
"When you look back … there was quite a bit of excitement," LeMoine said, of the findings. "What we are interested in is understanding the processes that are happening for those animals to be able to eat through plastic."
In Brandon, the researchers have dubbed the worms and bacteria "plastivores."
Glycol, a form of alcohol, was created as a byproduct of the plastic degradation, but LeMoine said the group is still working to identify the exact nature of the end products.
They're still studying why the waxworms and bacteria seem to work so well together.
"It's just a neat system to look at and we're really hoping to get the other side of the equation when we can," LeMoine said.
Lemoine's fellow researcher cautions it's not a one-stop solution to the world's growing plastic waste problem.
"Worms that eat our plastic waste and turn it into alcohol sounds too good to be true. And in a way it is," said Bryan 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," he said.
with files from Nicole Mortillaro