Enhancing Plastic Decomposition in Mealworms (Tenebrio molitor): The Role of Nutritional Amino Acids and Water

Certain insects, such as mealworms (Tenebrio molitor), have shown the ability to effectively biodecompose plastic waste under environmentally benign conditions. However, sustaining this biodecomposition within insect populations presents challenges, as high mortality rates and relatively slow decomposition rates limit the viability of large-scale plastic recycling. To enhance the process, protein-rich nutritional additives are usually necessary. Despite this, there has been little guidance on selecting suitable nutrients for plastic-eating insects like mealworms. In this systematic investigation, aqueous solutions of representative nonessential amino acids (NEAAs) and essential amino acids (EAAs) are used and compared as additives for the biodecomposition of polystyrene by mealworms. The study demonstrates that the essentiality and abundance of amino acids in mealworms significantly impact the rate of plastic biodecomposition. High-abundance EAAs, such as phenylalanine (Phe) and valine (Val), provide the most notable rate enhancements, while low-abundance NEAAs, such as cysteine (Cys), do not enhance the rate. The results also indicate that both water and individual free amino acid solutions effectively reduce cannibalistic behavior among mealworms, while enhancing their nutritional value. These findings provide a more rational basis for selecting cofeeds to improve this biodecomposition process.