Isolation and characterization of polyethylene terephthalate (PET) degrading bacteria and enzymes

Over the last century, plastic pollution has become a pressing environmental problem that calls for urgent action. Approximately 367 million tons of plastic were produced worldwide in 2020 and it is expected that by 2050 a total of 33 billion tons of plastic waste will have accumulated on the planet. Enzymatic hydrolysis of plastic polymers has been proposed as a sustainable plastic waste management policy that overcomes the limitations of current practices. Polyethylene terephthalate (PET) is one of the most widely used aromatic polymers in the plastic industry with applications in the production of water and soft-drinks bottles, food packaging and textiles. Over the last 17 years, several lipases, cutinases and carboxylesterases have been discovered to degrade PET. Since the discovery of Ideonella sakaiensis 201-F6 in 2016, a gram-negative bacterium from a PET-contaminated site that utilizes PET as its main carbon source, efforts have been made to identify new PET assimilating bacteria and their associated biochemical pathways. In this study, a culture-independent metagenomic approach and a culture-dependent isolation strategy were used to identify new PET degrading bacteria and enzymes from diverse environmental samples of plastic polluted sites in Denmark.