Optimizing polystyrene degradation, microbial community and metabolite analysis of intestinal flora of yellow mealworms, Tenebrio molitor

This study explored a direct feeding of expanded polystyrene as the sole diet for breeding Tenebrio molitor larvae. Temperature and relative humidity were manipulated to evaluate polystyrene biodegradation efficiency, survival rate, and formation of micro-polystyrene residue. Efficient conditions were at temperature of 25 °C with a humidity of 65 ± 5 %. Comparative metabolomic and metabolic-metabolic network analyses was performed for visualizing detailed pathway. Possibility of forming 4 (p)-hydroxyphenylacetic acid from phenylacetic acid with further conversion to 4-methylphenol, 4-hydroxybenzaldehyde, and 4-hydroxybenzoate could be seen as a side chain route for further biodegrading process. Key species identified in the gut of T. molitor larvae included Citrobacter sp., Serratia marcescens, Klebsiella aerogenes, and Klebsiella oxytoca. Pseudomonas aeruginosa was detected only under an anaerobic condition whereas Acinetobacter sp. was present only under an aerobic condition. These results demonstrate the potential to decrease micro-polystyrene by optimizing breeding conditions and biodegradation process of polystyrene.