The discovery of PET hydrolysis by a cutinase enzyme ~16 years ago, combined with the global pollution crisis caused by plastics waste in the environment has catalyzed a massive international community effort to discover, engineer, evolve, and implement a biological solution for polyester recycling. Prominent works from many groups in this field have demonstrated that enzymatic PET deconstruction is likely optimal near the glass transition temperature of the polymer (~70°C). To date, several thermotolerant enzymes to this end have been discovered, many originating from Thermobifida bacteria and related metagenomes.
Large strides have been made towards developing effective PET hydrolases using protein engineering tools, especially in terms of the ability to deconstruct amorphous PET substrates at large scale and to high conversion extents. However, if enzymes are to offer a viable solution to polyester recycling, there is an urgent need to be able to deconstruct crystalline substrates as well, found in single-use beverage bottles, carpets, and clothing. Indeed, we estimated that substantial savings from an economics, energy, and greenhouse gas emissions perspective could be avoided by reducing or removing mechanical pretreatment to make crystalline PET into an amorphous substrate for enzymatic hydrolysis.
With that motivation, we were interested to expand the suite of known thermotolerant enzymes and provide new scaffolds for the research and industrial communities. In this seminar I will present new data from the CEI, NREL and the BOTTLE consortium. As I will shortly be leaving my position at the University of Portsmouth, I will also share some details of my new position, taking up the lead of the World Plastics Summit in Monaco, which I hope will open new opportunities for collaborative research in this area.