Isolation of gut microorganisms from mealworms capable of degrading biodegradable plastic polybutylene succinate

Polybutylene succinate (PBS) is a biodegradable aliphatic polyester widely used in packaging materials, agricultural films, and disposable products. However, its slow degradation under natural conditions limits its environmental sustainability. This study examined the ability of Tenebrio molitor larvae (mealworms) to consume PBS and the associated gut microbial mechanism. Mealworms were fed diets with different PBS-to-bran ratios, and the PBS:bran (2:8) group showed the highest survival rate (79.39 ± 11.06 %) and stable growth. Gel permeation chromatography (GPC) of residual PBS in frass revealed a limited depolymerization (LD) pattern. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) increased by 63.76 % and 71.14 %, respectively, indicating partial chain scission and reaggregation of degraded fragments. Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analyses confirmed the cleavage of ester bonds and the formation of hydroxyl groups during digestion. Gut microbial analysis showed that Pseudomonas aeruginosa was a dominant strain involved in PBS degradation via lipase- and cutinase-mediated ester hydrolysis. These results demonstrate that mealworms can ingest and partially depolymerize PBS through microbial actions in the gut. This study offers a promising basis for bio-assisted and environmentally compatible strategies for the degradation and resource recovery of PBS waste.