Plastic Diets Drive Microbiome and Metabolic Reprogramming in Wax Moth Larvae ( <i>Achroia grisella</i> )

The burgeoning global plastic crisis necessitates transformative solutions beyond current recycling and disposal methods. This study investigates the ability of wax moth larvae (Achroia grisella) to biodegrade low-density polyethylene (LDPE) and polylactic acid (PLA), emphasizing the complex interactions between the physiology of larvae, their gut microbiome, and the plastic degradation process. Using 16S ribosomal RNA sequencing, Seahorse bioassays, and advanced metabolomic and lipidomic profiling, we demonstrate that plastic consumption is associated with microbial and metabolic restructuring in larvae. LDPE-fed larvae displayed elevated microbial diversity, dominated by Bacillus spp., which correlated with shifts in carbohydrate metabolism and amino acid biosynthesis pathways critical for energy production and detoxification. Conversely, PLA-fed larvae were enriched with Enterococcus spp., linked to oxidative stress mitigation and nucleotide turnover. These diet-induced adaptations, such as the proliferation of Bacillus spp. in LDPE‑fed larvae, known to express alkane‑hydroxylase enzymes that initiate polyethylene depolymerization, and enrichment of Enterococcus spp. in PLA‑fed larvae, linked to ester bond hydrolysis, underscore a symbiotic co-metabolism that may play a contributory role in plastic processing, albeit at the cost of reduced larval growth and suppressed mitochondrial function. By unraveling these complex biological interactions, this study establishes a foundation for harnessing insect-microbiome ecosystems to develop scalable and eco-friendly strategies for plastic waste management. Future research should explore the genetic and enzymatic mechanisms underpinning plastic metabolism in insect-microbiome ecosystems.