Food emulsifiers modulate polyethylene mass loss by Tenebrio molitor: Surface wettability and frass-associated gut-derived microbiome as correlates

Polyethylene (PE) is one of the most persistent plastic pollutants, and enhancing its removal by the mealworm Tenebrio molitor is of considerable interest. This study aimed to evaluate whether exogenous food emulsifiers modulate PE removal by T. molitor and to identify associated surface- and microbiome-level correlates. Four food-grade emulsifiers (Span 60, Tween 80, sodium stearoyl lactylate and glycerol monolaurate) were applied as 1% and 5% (w/v) aqueous pretreatments of PE films, which were then fed to T. molitor larvae for 21 days. PE removal ratio, larval survival, growth and pupation, film surface contact angle, bulk thermal properties of frass residues (TG/DTG), and frass-derived bacterial communities (16S rRNA V3-V4 sequencing, ecological and network analyses, FAPROTAX prediction) were quantified. Emulsifier effects were emulsifier- and concentration-dependent: 5% Span 60 achieved the highest PE removal ratio (60.44 ± 2.54%, about 10-fold of control) with high survival (79.33 ± 2.52%), whereas 5% Tween 80 significantly suppressed PE removal and larval fitness. In this study, PE removal ratio refers to mass-loss-based PE removal; direct mineralization was not quantified. Surface wettability modification, frass TG/DTG signatures and frass-microbiota community assembly covaried with emulsifier identity.