Studying the biochemical characteristics of enzymes with PET plastic degradation ability towards the understanding of their adaptation to the marine environments

The use of Polyethylene Terephthalate (PET) as plastic polymers has become an integral part of our daily life due to its many advantages, such as material robustness, and low-priced production. The increasing demand and use, have become a global problem since the amount of plastic production is greater than its recycling. This leads to the accumulation of massive plastic waste. Furthermore, microplastics are found in natural environments, including the ocean, and ends up in our food chain. In recent years, plastic biodegradation has gained increasing interest as an environment friendly promising solution. Following the discovery of enzymes, from metagenomics libraries, with PET degradation abilities into its fundamental building blocks, has increased the attempts to re-use them for new and good quality products. Metagenomics libraries enable us to homology search DNA sequences from environmental samples without the need of growing the organisms in the lab. Thus far no PET degrading enzyme from a marine origin has been characterized. By exploring metagenomics libraries of marine-originated DNA samples enabled us to identify homologs of PET hydrolyze enzymes. We surmise that the detailed biochemical characterization of activity in different environments (temperature, pH, salinity and oxygen levels), and comparison between the newly identified marine enzymes, soil originated enzymes, and ancestral sequence reconstruction of their evolutionary radiation, will enable us to study how these newly evolved enzymes adapted to their environment. Furthermore, insights gained from this work will enable the destining of new efficient enzymes towards effective PET recycling.