Polystyrene (PS) Degradation by Tenebrio molitor Larvae

Objectives : This study examined the degradation potential of PS by yellow mealworm larvae (Tenebrio molitor).Methods : PS degradation characteristics by mealworm larvae were investigated by supplying PS as a nutrient, and the intestinal microflora of mealworms were analyzed. Decomposition products of PS by mealworm larvae were identified by Fourier transform infrared spectroscopy (FTIR) and solid nuclear magnetic resonance (NMR).Results and Discussion : The maximum amount of PS degradation by mealworm larvae (about 14.3 mg/mealworm) was measured at 30℃ and 80% relative humidity, but the maximum peak degradation rate (0.154 mg/d/mealworm) was observed at 30℃ and 70% relative humidity. Most of the intestinal microorganisms of mealworms were identified as Proteobacteria except for some Firmicute, and new colonies such as Acinetobacter, Exiguobacterium, and Pseudomonas were appeared. A carbonyl group presumed to be a conversion product of PS (C-O-C vibration, 1118 cm-1, O-C=O stretch, 1644 cm-1) was observed.Conclusion : Maximum decomposition of PS by mealworm larvae was achieved at 30℃ and 80% relative humidity, and structural changes of PS were observed in the decomposition product. Isolation of the intestinal pure microorganisms contributing to PS degradation and stimulation of PS degradation by the microorganism should be conducted at a follow-up study.