Can the mealworm be the answer to Africa’s plastic waste problem?

As Africa, alongside the rest of the world, contends with a growing challenge of plastic waste, scientists from the International Centre of Insect Physiology and Ecology (icipe), have found a promising solution to the menace – in the mealworm.
 
In a paper published in Scientific Reports journal, the researchers report the potential of the lesser mealworm (the larvae of a darkling beetle species, known scientifically as Alphitobius), to consume plastic. The scientists have also noted a consortium of important bacteria in the gut of the mealworm, which 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.
 
Globally, more than 400 million tonnes of plastic are produced annually; less than 10% is recycled and an estimated 19 – 23 million tonnes end up in lakes, rivers and seas. 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 5% and consumes 4% 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 human, environment and biodiversity.


Lesser mealworms feeding on styrofoam

 
“Our study showed that the mealworms can ingest close to 50% 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,” says 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 defence strategy acquired after feeding on plastic.”
 
Additionally, the scientists will research 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,” 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.
 
 Darkling beetle species
Darkling beetle species


Notes for Editors

The International Centre of Insect Physiology and Ecology (www.icipe.org): headquartered in Nairobi, Kenya, is the only research institution in Africa working primarily on insects and other arthropods. The Centre conducts world-class science, and then translates this knowledge into innovate environmentally friendly, affordable, accessible and easy to use solutions to tackle crop pests and disease vectors. icipe’s role also extends to the conservation and sustainable exploitation of the beneficial insect biodiversity. Thus, icipe works through the 4Hs Themes – Human Health, Animal Health, Plant Health and Environmental Health – a holistic and integrated framework that has sustainable development as its basis, to improve food security, health and the overall well-being of communities in Africa. We gratefully acknowledge the support of icipe core donors: the Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); the Australian Centre for International Agricultural Research (ACIAR); the Government of Norway; the German Federal Ministry for Economic Cooperation and Development (BMZ); and the Government of the Republic of Kenya.
The views expressed herein do not necessarily reflect the official opinion of the donors.
 
Research details: Ndotono, E.W., Tanga, C.M., Kelemu, S. et al. Mitogenomic profiling and gut microbial analysis of the newly identified polystyrene-consuming lesser mealworm in Kenya. Sci Rep 14, 21370 (2024). https://doi.org/10.1038/s41598-024-72201-9
 
Corresponding authors: Fathiya Khamis (Fkhamis@icipre.org)

Funding: This research was funded by the following organizations and agencies:  Australian Centre for International Agricultural Research (ACIAR) (ProteinAfrica, Grant No: LS/2020/154), Novo nordisk fonden (Refugee Insect Production for Food and Feed (RefIPro), the Rockefeller Foundation (WAVE-IN-Grant No: 2021 FOD 030); Bill & Melinda Gates Foundation (INV-032416); IKEA Foundation (G-2204-02144); European Commission (NESTLER Project: 101060762 and INNOECOFOOD project: 101136739), the Curt Bergfors Foundation Food Planet Prize Award; Norwegian Agency for Development Cooperation, the Section for research, innovation, and higher education grant number RAF-3058 KEN-18/0005 (CAP-Africa);  Swedish International Development Cooperation Agency (Sida); Swiss Agency for Development and Cooperation (SDC); Australian Centre for International Agricultural Research (ACIAR); Government of Norway; German Federal Ministry for Economic Cooperation and Development (BMZ); and Government of the Republic of Kenya. The views expressed herein do not necessarily reflect the official opinion of the donors.”

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