Kenyan scientists have discovered that a native mealworm can eat and break down polystyrene – a breakthrough that could help tackle the continent's growing plastic waste crisis.
A research team in Kenya found that larvae of the lesser mealworm – a beetle species from the Alphitobius genus – can consume the widely used packaging material when combined with other nutrients.
Polystyrene is a plastic material widely used in food, electronic and industrial packaging, and is difficult to break down.
The discovery was made by researchers led by Fathiya Mbarak Khamis, a senior scientist with the Plant Health Theme, at the Icipe research centre in Duduville, near Nairobi.
The team had been studying insects as potential food sources.
Surprise find
Khamis told RFI the team unexpectedly spotted the insect in their chicken coop litter. It resembled the yellow mealworm found in Europe and the United States, already known to eat plastic.
"We identified it using molecular tools, and, since it is a close relative of the yellow mealworm, we decided to test if it could feed on plastic," Khamis said.
To confirm their theory, the researchers fed the larvae on three different diets over a month-long trial: polystyrene alone, bran alone, and a mixture of both.
Ghana grapples with crisis caused by world's throwaway fashion
Larvae given both polystyrene and bran survived better and ate more plastic than those fed polystyrene only. The combined diet group broke down nearly 12 percent of their total polystyrene intake.
So are the worms actually "eating" the plastic?
"Yes, these insects are digesting it; they are feeding on it ... and surviving on it. When you introduce the bran, it increased the survival level because of course it has other nutrients," Khamis explained.
Role of gut bacteria
The real breakthrough may lie not just in the mealworms themselves, but in the bacteria in their guts. Analysis showed significant changes in the larvae’s gut bacteria depending on their diet.
Larvae fed on polystyrene had higher levels of bacteria like proteobacteria and firmicutes, known for their ability to adapt to various environments and break down complex substances.
Other bacteria, including kluyvera and klebsiella, were also abundant and are capable of producing enzymes that digest synthetic plastics.
“It is possible that mealworms might not naturally have the ability to eat plastic but that, instead, the bacteria in their guts might change when they start eating plastic, to help break it down,” said Khamis.
This raises the possibility of isolating these bacteria and their enzymes to create large-scale solutions for plastic waste.
Waste crisis
By studying these natural plastic-eaters, the team hopes to create new tools that will get rid of plastic waste faster and more efficiently.
Khamis believes the lesser mealworm’s discovery is particularly important for Africa, where plastic waste is a growing problem due to high imports, low re-use, and limited recycling infrastructure.
Traditional recycling methods – like chemical and thermal processing – are expensive and can create other pollutants.
“The insects and environmental conditions in Africa may differ from those in other parts of the world,” she said, suggesting that the findings could lead to solutions tailored to African settings.
What's needed to make that happen, Khamis concludes, is more funding from both the public and private sectors.
