Biodegradation of Polystyrene by Plastic-Eating Tenebrionidae Larvae.

Polystyrene (PS) is an extremely stable polymer with a relatively high molecular weight and a strong hydrophobic character that makes it highly resistant to biodegradation. In this study, PS was subjected to biodegradation tests by () and () larvae. Specifically, six different experimental diets were compared: (i) fed with bran; (ii) fed only PS; (iii) fed only PS treated with HO; (iv) fed with bran; (v) fed only PS; and (vi) fed only PS treated with HO. Therefore, the mass change of the larvae and the survival rate were measured periodically, while the frass collected after 15 and 30 days was analyzed by different analyses, such as spectroscopy (FTIR), spectrometry (molecular weight and polydispersity), thermal analysis (TGA) and microscopy (scanning electron microscopy observations). The obtained results suggest that in the case of larvae, larvae feeding on bran showed the highest survival rate of ~94% at 30 days, while in the case of the larvae, the highest survival rate was exhibited by larvae eating PS-HO. Although not strongly pronounced, the M and M of PS in the frass of both and larvae decreased over 30 days, suggesting PS biodegradation. Finally, the morphological analysis shows that PS samples isolated from the frass of and larvae showed completely different, rough and irregularly carved surface structures, in comparison to PS before biodegradation.