In an innovative approach to tackling plastic pollution, a team of scientists from the International Centre of Insect Physiology and Ecology has discovered that Kenyan lesser mealworm larvae can consume polystyrene a common yet hard-to-recycle plastic. This is the first time an insect species native to Africa has been found to break down polystyrene, adding it to a small but promising group of plastic-degrading insects.
How Do They Do It?
Polystyrene, often known as Styrofoam, is widely used in packaging and is notoriously difficult to recycle due to its durable nature. While traditional recycling methods are costly and polluting, the Kenyan lesser mealworm has a unique ability to chew through polystyrene with the help of gut bacteria that aid in breaking down the plastic. These larvae, the immature form of the Alphitobius darkling beetle, thrive in poultry houses, a warm and food-abundant environment ideal for their growth.
The Experiment
The research team conducted a month-long trial to observe the larvae’s ability to break down polystyrene. They fed groups of larvae three diets: polystyrene alone, bran alone, and a mix of polystyrene and bran. The larvae on the polystyrene-bran diet showed higher survival rates and were more efficient at breaking down the plastic than those fed solely on polystyrene.
These findings emphasize that a nutrient-dense diet supports the larvae’s ability to degrade plastic effectively, likely due to the energy derived from carbon and hydrogen components in the plastic.
On a polystyrene-bran diet, the larvae were able to break down around 11.7% of the polystyrene over the study period. This demonstrated the importance of nutrition in aiding plastic degradation and confirmed that a balanced diet enhances the larvae’s efficiency.
Role of Gut Bacteria
The researchers analyzed changes in the larvae’s gut bacteria, which they believe play a key role in plastic breakdown. Larvae fed on polystyrene developed increased populations of bacteria such as Proteobacteria, Firmicutes, and species like Kluyvera, Lactococcus, Citrobacter, and Klebsiella all known to produce enzymes capable of degrading synthetic plastics. These bacteria may adapt to the unusual diet and could potentially be harnessed for large-scale plastic degradation without posing environmental risks.
Future Applications and Scaling Up
While other insect species, such as yellow mealworms and superworms, have demonstrated similar plastic-degrading abilities, this is one of the first studies focusing on insects native to Africa. This regional focus is crucial as African countries face unique challenges in plastic waste management. By isolating the specific bacteria and enzymes responsible for breaking down polystyrene, the team hopes to develop microbial solutions that could be applied at scale in recycling facilities and landfills.
Moving forward, research will aim to produce these enzymes in large quantities and explore the larvae’s potential to break down other types of plastic. Developing sustainable methods to ensure the insects’ health during prolonged plastic consumption and investigating the safety of using their biomass in animal feed are also key priorities. This discovery holds promise for transforming plastic pollution control efforts, particularly in African nations with critical plastic waste issues.