Degradation of High-Density Polyethylene (HDPE) Film by Bacterial Consortium

The current study found that, although the metabolic pathways of polyethylene (PE) degradation can be studied with pure strains, the degradation of PE mulch in the environment as a result of the synergistic action of different microorganisms has been ignored. This limitation can be overcome by the use of microbial consortia. In this study, three Bacillus species were isolated and purified, namely B. cereus, B. parapsilosis and B. megaterium. The strain consortium NLJ-1 and its produced crude enzyme mixture MCE were cultured for 60 days in a medium with PE film as the sole carbon source. The removal of PE film from NLJ-1 was up to 31.3%, while the removal of MCE was 24.5%. The samples were characterized by SEM, GPC, FTIR, XPS, XRD, and GC-MS. It was found that the surface of the PE was broken and that the low molecular weight PE chains were degraded first, with the appearance of new oxygen-containing functional groups. Its chemical inertness was also greatly reduced. Finally, the mechanism of enzymatic degradation of PE was revealed. This study enriches the biological resources for PE degradation and provides an example of species interactions for the degradation.