Novel PET hydrolase derived from thermophilic microorganisms

Plastics have become ubiquitous in our daily life, due to their significant properties. However, the nature of the polymers constituting plastic materials makes them persistent in the environment. The resulting growth in the quantity of plastics waste has emerged as a pressing issue. In recent years, biodegradation approaches have demonstrated valuable potential in degrading plastics through the action of enzymes, bringing low environmental impact. In 2016, a bacterial strain called Ideonella sakaiensis 201-F6 was identified for its abilities to produce two unique enzymes, the polyethylene terephthalate hydrolase (PETase) and the mono (2-hydroxyethyl) terephthalic acid hydrolase (MHETase). These enzymes enable the bacteria to utilize polyethylene terephthalate (PET) as their sole carbon source. In this scenario, extensive research has been carried out for the identification of other bacterial strains able to produce enzymes exploitable for the plastic degradation. Starting from these bases, the identification of new bacterial hydrolases deriving from thermophilic microorganisms can give new insight into plastic biodegradation in harsh conditions, such as high temperatures. Through meta-genomic approaches, a novel thermophilic PET hydrolase, has been recently identified from geothermal samples. This novel enzyme, denominated PP PETase (PP), was produced in recombinant form and purified to carry on it physico-chemical analyses and assess the thermal stability and structural features of PP to provide deeper insights into its functional and structural properties and identify its potential applications.