Degradation behaviour and microbial action of polybutylene adipate terephthalate membranes in soil and composting environments

The development of degradable plastic has emerged as a critical strategy to address plastic pollution. This study focuses on polybutylene adipate terephthalate (PBAT) as the subject of investigation, systematically exploring its degradation behavior and microbial mechanisms in soil environments. Microorganisms such as Escherichia coli ( E. coli ), Staphylococcus aureus ( S. aureus ), and Bacillus flexus ( B. flexus ) were introduced, and the degradation efficiency and mechanisms of PBAT were analyzed under varying conditions of temperature (45, 55, and 65 ℃), ventilation (100 and 200   mL/min), and burial depth. The experimental results revealed that E. coli , under 100   mL/min ventilation at 55 ℃, exhibited the highest degradation efficiency, with a weight loss rate of 16.45% in 30 days, significantly outperforming the other strains ( S. aureus : 12.49%; B. flexus : 3.54%). It was found that the presence of surface cracks and ester bond (C=O, 1710   cm⁻¹) rupture by SEM and FTIR analysis, and degradation occurs preferentially in the amorphous zone and that crystallinity increases throughout the degradation process by XRD and DSC results. This study elucidates PBAT degradation was catalyzed by microorganisms through the secretion of key enzymes providing a novel foundation for optimizing the environmental application of degradable plastic and advancing green technology development.