Fermentation-weakened BF/PBAT film facilitates Tenebrio molitor consumption: Prolonged larval longevity maximizes PBAT biodegradation and soil metabolic activity

Plastic packaging causes significant environmental pollution despite its widespread use and convenience. To address the adverse environmental impact of plastic packaging, substituting traditional plastics with biodegradable polymers and degrading them via composting or soil burial has emerged as a mitigation strategy. However, various factors impede degradation efficiency during these processes, extending degradation times and increasing costs. This study introduced an innovative fully biodegradable film composed of bamboo fiber (BF) and poly(butylene succinate-co-terephthalate) (PBAT), utilizing Tenebrio molitor larvae for biological erosion to generate metabolites that rapidly degrade in soil. To enhance larval consumption, we employed novel strategies: extending the larval period to 17 weeks through low-temperature (18 °C) and prolonged light exposure (24 h), and pretreating films with solid-state fermentation (SSF) to reduce puncture strength to 0.018 MPa. The results indicate that under extended larval conditions, total film consumption reached ∼300 g per 100 larvae; after bioerosion, PBAT molecular weight decreased by ∼10-fold; and metabolized BF/PBAT film residues achieved complete soil homogenization within 4 weeks, enabling rapid degradation while reducing processing time and costs.