Abstract Summary/Description
Plastic and petroleum hydrocarbon pollution have become ubiquitous in natural and man-made environments, alarming concerns about serious harm to humans and nature. Polyethylene terephthalate (PET) plastics and petroleum are used widely worldwide, and their pollution has become a global concern. Our previous studies demonstrated that a novel anaerobic bacterium Sporomusaceae strain BFN5 isolated from oil spill-impacted salt marsh sediment can degrade various plastics and aromatic hydrocarbons. This study investigated physiological and molecular mechanisms of anaerobic degradation of PET by strain BFN5 and aimed to elucidate the accelerating conditions for PET and aromatic hydrocarbon degradation. Strain BFN5 was anaerobically cultured with PET microplastic (< 5mm), naphthalene, benzene or toluene as a carbon source and nitrate as an electron acceptor. The plastic degradation rates were measured via weight loss studies. Post-incubation resulted in significant PET degradation (1.43%/month) in strain BFN5 cultures, with a calculated total degradation time of 9.24 years, compared to known abiotic degradation times of 16-48 years. Increased biofilm formation was indicative of more efficient PET degradation and was quantified. Topology of the biofilms on PET microplastics and PET surface morphology changes were analyzed via Confocal Laser Scanning Microscopy and Scanning Electron Microscopy. Genes involved in anaerobic PET and aromatic hydrocarbon degradation pathways were identified via genomic analysis. Transcript level analyses for putative plastic and aromatic degradation genes such as buk, ubiD, and ncrA are underway to unravel the metabolic pathways of strain BFN5. The ultimate aim of this study is to provide effective bioremediation solutions for plastic and petroleum wastes.
