By Sharon Atieno
The larvae of a darkling beetle species that is indigenous in Africa, could be the solution to combating plastic waste on the continent and the rest of the world.
This is according to research conducted by scientists from the International Centre of Insect Physiology and Ecology (icipe).
Globally, more than 400 million tonnes of plastic are produced annually. While less than 10% is recycled, an estimated 19 – 23 million tonnes end up in lakes, rivers, and seas.
The study found that the lesser mealworm, the larvae of the Alphitobius beetle species, has the potential to consume and degrade polystyrene (PS) a major microplastic that is mounting up in land and water bodies.
The annual production of PS is estimated at 20 million metric tons. Its waste comes from the commercial use of its common form, Styrofoam, which is used for various applications such as food storage containers, packaging of equipment, disposable plates and cups and insulation in construction.
According to the study, the lesser mealworms, considered a major pest in poultry production, ingested nearly 50% of the styrofoam converting it to carbon dioxide.
The researchers observed that several important bacteria in the gut of the mealworm help in the digestion of plastic. Thus, 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. However, this is the first time that the lesser mealworms, which are native to Africa, have been documented to have this capacity,” explains Dr Fathiya Khamis, icipe Senior Scientist, and lead researcher of the study.
Other insect species such as the greater wax moth (Galleria mellonella) and super worms (Zophobas morio) have also been identified to have the same abilities as mealworms to degrade plastic and convert it into non-hazardous compounds.
“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 Evalyne Ndotono, an icipe PhD scholar.
“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 defense strategy acquired after feeding on plastic.”
Additionally, the scientists will research the ability of the lesser mealworm to degrade diverse types of plastics and convert them 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,” states Dr Abdou Tenkouano, icipe Director General.
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.
