‘Superworm’ could help fix trash crisis
Scientists across the world are trying to find bacteria and bugs that consume rubbish. A plastics-consuming worm is the latest, reports Pranshu Verma.
Aplump larva the length of a paper clip can survive on the material that makes Styrofoam. The organism, commonly called a ‘‘superworm’’, could transform the way waste managers dispose of one of the most common components in landfills, researchers say, potentially slowing a mounting rubbish crisis that is exacerbating climate change.
In a paper released this month in the Microbial Genomics journal, scientists from the University of Queensland in Brisbane showed that the larvae of a darkling beetle, called zophobas morio, can survive solely on polystyrene, commonly called Styrofoam.
The findings come amid a flurry of research on ways bacteria and other organisms can consume plastic materials, like Styrofoam and drinking bottles.
Now, the researchers will study the enzymes that allow the superworm to digest Styrofoam, as they look for a way to transform the finding into a commercial product.
Industrial adoption offers a tantalising scenario: A natural way to dispose of and recycle the Styrofoam trash that accounts for as much as 30% of landfill space worldwide.
‘‘You cannot really escape plastic any more – plastic waste is everywhere,’’ says study coauthor Christian Rinke. ‘‘This is definitely a new, arguably, better, environmentally friendly way to break [it] down.’’
The world is facing a plastic crisis. Each year, half of all plastic designed for single use – things like bottles, Styrofoam cups and shopping bags – becomes trash, clogging up landfills and decomposing slowly while releasing noxious greenhouse gases, according to the UN Environment Programme.
More than 14 million tons end up in the water every year, data show, killing animals and degrading underwater habitats.
Among plastics, Styrofoam is particularly troublesome. The material takes up a lot of space, making it expensive to store at waste management facilities, industry experts say.
The cups, plates and other materials made from it are also often contaminated with food and drink, making it hard to recycle. Polystyrene fills landfills, where it can often take 500 years to break down and decompose, researchers have found.
As the rubbish crisis escalates, scientists across the world are trying to find bacteria and other living organisms that naturally dispose of plastic waste.
In 2015, researchers from Stanford University revealed that mealworms could also survive on Styrofoam. The next year, Japanese scientists found bacteria that could eat plastic bottles.
In April, researchers from the University of Texas found an enzyme which could digest polyethylene terephthalate, a plastic resin found in clothes, liquid and food containers.
Wei-min Wu, a senior researcher at Stanford University who led its mealworm study, says there has been a growing chorus of researchers looking for natural solutions to recycle plastic because of the environmental risks.
He says many researchers in this field, including the ones from Australia, will face several challenges in the years ahead.
It will take time to study the gut enzymes of things like mealworms and superworms, and when they do, it is not guaranteed they can digest plastics at large levels at a very quick and efficient rate.
Rinke was excited by his research results but noted it would take time to develop into an industrial solution, somewhere between five and 10 years.
To conduct the study, his research team in Australia fed the superworms three separate diets. One group was given a ‘‘healthy’’ solution of bran, the second, polystyrene, and the third was put on a starvation diet.
Ninety per cent of the larvae that ate bran became beetles, compared with roughly 66% from the group given polystyrene and 10% from those forced to starve. This indicated to researchers that superworms have enzymes in their gut that can effectively digest Styrofoam.
Next, the scientists will study those enzymes to see how well they can digest polystyrene on a large scale – modifying them if necessary to become more effective. ‘‘We want to not have gigantic superworm farms,’’ Rinke says. ‘‘Rather, we want to focus on the enzyme.’’
If the research proves successful, Rinke says waste managers could collect and grind Styrofoam materials and put them into a liquid solution made with the superworm enzyme.
The solution would ideally dispose of the Styrofoam or digest it in a way that allows new plastic products to be created, thereby reducing the need for new plastic materials, he says.
‘‘If you can go all the way to the end, the idea is to use the system and come up with a biological solution to recycle plastic.’’
Despite the findings from Rinke and others, there are reasons that none has successfully translated into industry applications over the past decade, researchers say.
Andrew Ellington, a professor of molecular biosciences at the University of Texas at Austin, says it has been difficult to find a plastic-digesting organism or enzyme that can operate in industrial conditions, which often process trash in very hot environments or through the use of organic solvents.
‘‘When you find something on a beach or you find something in a worm gut, that’s great, but all the enzymes in that thing work pretty much under the conditions where you found it,’’ he says. ‘‘And those may not be industrial conditions.’’
He adds that even if researchers decide not to extract enzymes and simply flood landfills with Styrofoam-eating worms, problems will occur.
Landfills combine all types of plastics together, and separating Styrofoam from other trash to let worms eat the pile would be cumbersome and costly.
He suggested an alternative solution. ‘‘I believe that we will be able to offer up, in the not-sodistant future, worm-based composting kits so that individuals can do this themselves.’’
Jeremy O’Brien, director of applied research at the Solid Waste Association of North America, says there are other business challenges in putting this type of solution into use.
As envisioned, the solution would require waste managers to collect Styrofoam separately from other trash, he says, which makes it cost-prohibitive.
O’Brien also says it remains unclear what kind of organic waste the enzyme process would generate, and he worries it could harm the micro-organisms landfills already use to process rubbish and reduce odours.
He adds that a more desirable and cost-effective solution would be to take Styrofoam in landfills and condense them enough so that they can be turned into new plastics. ‘‘That’s a lot simpler solution.’’