Objective A highly efficient polybutylene adipate terephthalate (PBAT)-degrading bacterial strain was isolated and identified for the development of a biological environmental protecting agent.

Method Using PBAT as the sole carbon source, bacterial strains with the copolymer degradation capability were isolated from compost samples using enrichment culture techniques. The isolate was identified based on morphological characteristics and 16S rDNA phylogenetic analysis. Film degrading efficiency of the isolate was measured by the loss of PBAT mass. The process and material changes of PBAT degradation were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water contact angle (WCA) measurements, and high-performance liquid chromatography (HPLC).

Result The potent PBAT-degrading strain, coded NF, was identified as Thermobifida fusca. After 6d of co-cultivation with a PBAT film in an LB medium at 55°C, it exhibited a significant degradation capacity with a 97.11% loss of PBAT in mass. A significantly increased absorption peak in the carbonyl region on the FTIR spectrum indicated cleavage of the ester bonds of PBAT as the film was degraded. The SEM image of the pronounced erosion with numerous holes and cracks on the surface of the film confirmed structure damage. Additionally, the WCA measurements signified a rise in hydrophilicity of the film being significantly altered and degraded by the presence of NF.

Conclusion The identification of PBAT-degrading T. fusca in the study added a new venue for studying degradation of packaging films as well as research on environmental protection through better understanding the functional enzymes and pathways associated with biodegradation of man-made polymeric materials.