Biotechnological treatment of polyethylene terephthalate mixed plastic streams

In the recent number of years, a great deal of attention has been given to biotechnological treatment of plastic waste because this option is considered as an efficient and generally greener approach for the depolymerization and upcycling of recalcitrant plastics in comparison to conventional mechanical and chemical processes. Moreover, plastic waste is often physically mixed combining recalcitrant petroleum based plastics together with bioplastics, forming (petro-bio)plastic streams, posing a substantial drawback to mechanical recycling and strongly impeding the development of sustainable end-of-life treatments. This inherent mixing of these streams means even existing advanced sorting techniques are unable to economically separate these (petro-bio)plastic streams, resulting in the dramatic deterioration of the original properties of the component plastics in particular petroleum-based plastic waste recycling streams. Our recent efforts include the exploration of biotechnological approaches to recycle single polyethylene terephthalate (PET) plastic and PET mixed with model bioplastics. We use different methods, from newly identified bacterial strains to commercial enzymes to deliver efficient depolymerization of single and mixed plastics, which can be followed by bio-upcycling into added-value biopolymers (i.e. bacterial nanocellulose). These biotechnological approaches pave the way for sustainable management routes for challenging mixed (petro-bio)plastic waste and prepares opportunities for its participation in the circular production of sustainable eco-polymers.