Facing our plastic waste crisis: biorecycling as a promising solution

Abstract

We are in a global plastic waste crisis. Plastic production has steadily increased over the last half century, while recycling rates remain as low as 9% in some nations, including Australia. Most plastic waste ends up in landfill or the environment as a lost resource, triggering the production of more virgin plastic to satisfy demands. Shifting away from this wasteful, linear economy towards a circular economy, where waste products are treated as a valuable resource and are recycled, will require considerable innovative advancements to our current plastic recycling methods. Biological recycling (biorecycling) has emerged as a promising solution, with several advantages over mechanical and chemical recycling. Using enzymatic reactions, long plastic polymers are cut into monomers without the need for high temperatures or chemical catalysts, and without affecting product quality. Biorecycling allows sustainable, commercially viable and near-infinite recycling of synthetic polymers. In this paper, we discuss reasons for our current plastic waste crisis, compare plastic recycling methods with a focus on biorecycling and explore commercial ventures of enzyme-based recycling technologies. We present recent developments in enzyme discovery, enzyme characterisations and protein engineering. Finally, we propose a strategy to move towards a circular plastic economy, by embracing biorecycling.