An important environmental issue is the pollution caused by poly(ethylene terephthalate) (PET) and the emitted monomers terephthalic acid (TPA) and ethylene glycol (EG). The TPA biodegradation pathway has been well documented for the microbial biodegradation and assimilation of PET; however, the PET biodegradation process by marine microorganisms via the EG biodegradation pathway is less understood. Here, we demonstrate how the marine bacteria Pseudomonas chengduensis BC1815’s membrane-anchored PET esterase (OF113_10420) breaks down PET. We also explain the characteristics of this enzyme and demonstrate that the strain assimilates PET via the EG biodegradation pathway. In addition to depolymerizing PET, PET esterase (OF113_10420) hydrolyzes BHET and MHET to generate EG more efficiently in alkaline circumstances. It has been discovered that P. chengduensis BC1815 cells exhibiting surface-displayed PET esterase (OF113_10420) have the potential to function as cell biocatalysts for the breakdown of PET. Additionally, we look into the microbial communities that have PET esterase linked to the EG biodegradation pathway, primarily those belonging to the phyla Proteobacteria and Actinobacteriota. Consequently, research on the microbial absorption and biodegradation of PET via the EG metabolism route increases our knowledge of the bioremediation of PET pollution in the marine environment and contributes to our understanding of the environmental destiny of PET pollutants in the marine environment.
Evidence for microbial biodegradation of polyethylene terephthalate (PET) has been reported, but little is known about the PET biodegradation process and molecular mechanism by marine microorganisms. Here, we show the biodegradation of PET by the membrane-anchored PET esterase from the marine bacterium Rhodococcus pyridinivorans P23, elucidate the properties of this enzyme, and propose the PET biodegradation by this strain in biofilm. We identify the PET-degrading enzyme dubbed PET esterase through activity tracking. In addition to depolymerizing PET, it hydrolyzes MHET into TPA under acid conditions. We prove that it is a low and constitutively transcribed, membrane-anchored protein displayed on the cell surface. Furthermore, we also investigate the microbial groups possessing PET esterase coupled with the TPA degradation pathway, mainly in the phyla Proteobacteria and Actinobacteriota . Clarification of the microbial PET biodegradation in the marine environment will contribute to the understanding of bioremediation of marine PET pollution.