What if the key to our fight against plastic pollution was inside the gut of an insect?
A recent scientific discovery sheds light on a species of worm capable of degrading polystyrene, paving the way for novel and eco-friendly solutions to manage our plastic waste.
a) Block of polystyrene before consumption.
b) Block of polystyrene after 30 days, showing holes and tunnels.
c) Mealworms fed with polystyrene and bran.
d) Mealworms fed exclusively with polystyrene.
Plastic, the miracle material of the 20th century, has become an environmental plague. Its annual production is estimated at 500 million metric tons (approx. 550 million tons), with a large portion ending up in landfills or oceans. The infamous "7th continent," a massive accumulation of floating debris in the Pacific, illustrates the severity of the issue, covering a surface area of 1.6 million square kilometers (approx. 620,000 square miles).
Among the most problematic plastics is polystyrene, a widely used but difficult-to-recycle material. Its applications, ranging from food packaging to insulation, generate nearly 20 million metric tons (approx. 22 million tons) of waste each year, often handled through polluting methods.
Biological solutions are beginning to emerge, and a recent study conducted by ICIPE (International Centre of Insect Physiology and Ecology) in Kenya revealed the existence of a mealworm capable of breaking down polystyrene thanks to its gut microbiota. This worm, a subspecies of
Alphitobius, could become a key player in sustainable recycling.
Researchers observed that these worms degrade polystyrene more efficiently when they are on a mixed diet that includes nutrients. Fed with a mixture of bran and plastic, they degraded 11.7% of the polystyrene within a month. Conversely, an exclusive plastic diet limits their effectiveness.
The sequencing of their microbiome revealed specific bacteria, such as
Klebsiella and
Citrobacter, which are capable of producing enzymes that break down synthetic polymers. These bacteria could be isolated for large-scale use (obviously, there is no question of massively spreading insects to combat pollution).
This discovery is particularly promising for regions heavily impacted by plastic pollution, such as Africa, where recycling facilities are insufficient. Local conditions offer unique opportunities to adapt this solution to regional needs.
However, challenges remain. It will be necessary to determine whether the enzymes from these bacteria can be produced on an industrial scale and to assess their effectiveness on other types of plastics. The ecological and health impacts of this method will also need to be studied.
By combining biological innovations with local strategies, insects could well become our allies in reducing plastic waste, ushering in a new era in modern pollutant management.
What is polystyrene?
Polystyrene is a synthetic polymer made from styrene, a liquid hydrocarbon derived from petroleum. It is one of the most common plastics due to its low production cost and great versatility.
It is available in two main forms: rigid and expanded. Rigid polystyrene is used for items like plastic cutlery or CD cases, while expanded polystyrene (or foam) is used for packaging or thermal insulation.
This material is valued for its lightness, mechanical strength, and insulating properties. However, it is extremely difficult to recycle and takes hundreds of years to decompose in nature.
Its durability poses a major pollution problem, particularly in the oceans, where it accumulates as harmful microplastics for marine wildlife.
Article author: Cédric DEPOND