Biodegradation of Polystyrene Paper Using Chewing Insects

Plastic pollution, particularly from polystyrene, has emerged as a serious environmental concern, prompting growing interest in its biodegradation. We investigated the potential of four chewing insects; meal-worm (Tenebrio molitor), superworm (Zophobas morio), American cockroach (Periplaneta americana), and cricket (Gryllus bimaculatus) to biodegrade polystyrene paper (PSP).

Using a randomized complete block design, four chewing insects were divided into two groups after 48-hour fasting with water. One group received PSP only; the other received PSP mixed with tapioca starch. Weight loss of PSP was recorded after 72 hours.

Z. morio demonstrated the highest degradation efficiency for PSP (92.10%), followed by P. americana (32.17%). When tapioca starch was added, Z. morio remained the highest effective (95.45%), followed by T. molitor (59.15%). Supplementing starch significantly enhanced degradation rates (P < 0.05). Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) revealed signs of depolymerization, oxidation, and surface cracking. FTIR indicated new functional groups of carbonyl (C=O, 1650 cm^-1) and hydroxyl (O-H, 3200-3550 and 3584-3700 cm^-1).

Certain chewing insects, especially Z. morio and T. molitor, possess strong potential for PSP degradation, likely aided by their gut microbiota. Notably, this study is the first to report PSP degradation by P. americana and G. bimaculatus. Further research is needed to explore the microbial mechanisms within insect guts that facilitate plastic biodegradation.