ICIPE discovers insect that degrades plastic waste

The International Center of Insect Physiology and Ecology (ICIPE) researchers have discovered an insect that could be helpful in addressing the plastic waste menace. 

The scientists say the larvae of lesser mealworm, a species of darkling beetle known scientifically as Alphitobius, are capable of consuming plastics, which have contributed to the global pollution menace. 

ICIPE senior scientist Fathiya Khamis, lead researcher of the study, said the researchers have also identified a consortium of important bacteria in the gut of the mealworm, which helps in the digestion of plastic.

From the studies, either the mealworm or the bacteria could be harnessed to biodegrade plastic.

“Although often mistaken for ordinary worms, mealworms are the larvae of the darkling beetles. Worldwide, yellow mealworms, the larvae of a darkling beetle species called Tenebrio molitor, have been used to biodegrade plastic," explained Dr Khamis.

She added: "However, this is the first time that the lesser mealworms, which are native to Africa, have been documented to have this capacity.” 

Globally, more than 400 million tonnes of plastic are produced annually. Less than 10 per cent is recycled and an estimated 19 – 23 million tonnes end up in lakes, rivers and seas, according to the United Nations Environment Programme.

Plastics may contain toxic chemicals, and the waste contaminates water, affects quality of soils, ecosystems and essential services, creates breeding grounds for mosquitoes, and ends up in the food chain.

While Africa produces only five per cent and consumes four per cent of global plastic, there is increased use of single-use plastic. The continent is now the world’s second most polluted.

The ICIPE researchers tested the ability of the lesser mealworm to consume polystyrene, one of the major microplastics that is fast accumulating both in land and water bodies. Polystyrene waste comes from the commercial application of its most common form, styrofoam.

This material is used in food storage containers, packaging of equipment, disposable plates and cups, and insulation in construction.

Various methods, including chemical, thermal and mechanical, are used to recycle polystyrene.

However, these approaches are expensive and they also produce toxic compounds that are harmful to humans, environment and biodiversity.

ICIPE PhD scholar Evalyne Ndotono said studies showed that the mealworms can ingest close to 50 per cent of the styrofoam. 

"We aim to conduct further studies to understand the process through which mealworms consume polystyrene, and whether they gain any nutritional benefits from the material,” said Ms Ndotono.

 She added: "We will also explore the mechanisms of the bacteria in the lesser mealworm in the degradation of plastic. We want to understand if the bacteria are inherent in the mealworms, or if they are a defence strategy acquired after feeding on plastic.”

ICIPE Director General  Abdou Tenkouano said they will carry further research to see the ability of the lesser mealworm to degrade diverse types of plastics and to convert it into useful, safe products. 

“Our research boosts ICIPE’s growing body of innovations for a circular economy. We can exploit this knowledge to solve the plastic waste pollution, while also harnessing the benefits of mealworms, which are part of the population of highly nutritious edible insects,” said Dr Tenkouano.

The ICIPE study also increases knowledge on bioremediation – the use of microbes to clean up contaminated ecosystems soil and groundwater applications.

The Centre will explore collaborative research and innovation efforts with other scientists, policymakers and industry partners, to harness the full potential of lesser mealworms and other similar organisms.

[email protected]