Ideonella Sakaiensis: a biotechnological tool to manage PET waste in the future

Plastic pollution is one of the most relevant environmental problems of our century. Plastic production has increased dramatically since the 1950s, reaching 360 billion tons in 2019. Polyethylene Terephthalate (PET) and other plastics manufactured by packaging industry account for 26% of the world's production and this number is expected to increase, reaching 318 million tons in 2050. Due to plastic recalcitrance to degradation and poor waste management systems, plastics tend to accumulate in the environment, especially in the oceans. It is estimated that 8 million tons of plastics leak into the ocean every year; at the actual rate in 2050, plastic will outnumber fishes in the ocean. Moreover, once in the ocean, plastics break down in microplastics and nanoplastics, becoming a threat for the environment, marine species and eventually for human beings. In the coming years, a remedy to this problem will have to be found. A promising solution to reduce PET pollution is given by Ideonella Sakaiensis. This bacterium can degrade PET more efficiently than other known PET-degrading bacteria. I. Sakaiensis is able to use PET as its major energy and carbon source, resulting in its complete oxidation and production of CO2 and H2O. The process is catalyzed by two enzymes, PETase and MHETase. Although these enzymes are more effective than other PET-hydrolyzing enzymes, it is not yet possible to apply them at an industrial level due to low thermo-stability and efficiency; so different research groups are trying to engineer them. Once strains that meet industrial needs are identified, they can be used in different applications, such as in PET-waste management facilities or in bioremediation programs.