The article describes the development of an improved PET hydrolase enzyme to break down and recycle plastic bottles. The researchers used enzyme engineering to enhance the activity and thermostability of a leaf-branch compost cutinase (LCC) enzyme, which is known for its high efficiency in depolymerizing PET. Through mutagenesis and the introduction of a disulfide bridge, they created variants of LCC that showed significant improvements in both activity and stability. These variants achieved a minimum of 90% PET depolymerization into monomers over 10 hours, with a productivity of 16.7 grams of terephthalate per liter per hour. The optimized enzyme outperformed all previously reported PET hydrolases, including those from the bacterium *Ideonella sakaiensis*. The researchers also demonstrated that biologically recycled PET could be produced from enzymatically depolymerized waste, which can then be processed into new bottles, contributing to a circular economy for PET. The process was scaled up in a pilot plant, and the resulting terephthalic acid monomers were successfully used to synthesize PET, showing mechanical properties comparable to those of commercial PET. This work addresses the global issue of plastic disposal and supports sustainability goals and the concept of a circular economy.The article describes the development of an improved PET hydrolase enzyme to break down and recycle plastic bottles. The researchers used enzyme engineering to enhance the activity and thermostability of a leaf-branch compost cutinase (LCC) enzyme, which is known for its high efficiency in depolymerizing PET. Through mutagenesis and the introduction of a disulfide bridge, they created variants of LCC that showed significant improvements in both activity and stability. These variants achieved a minimum of 90% PET depolymerization into monomers over 10 hours, with a productivity of 16.7 grams of terephthalate per liter per hour. The optimized enzyme outperformed all previously reported PET hydrolases, including those from the bacterium *Ideonella sakaiensis*. The researchers also demonstrated that biologically recycled PET could be produced from enzymatically depolymerized waste, which can then be processed into new bottles, contributing to a circular economy for PET. The process was scaled up in a pilot plant, and the resulting terephthalic acid monomers were successfully used to synthesize PET, showing mechanical properties comparable to those of commercial PET. This work addresses the global issue of plastic disposal and supports sustainability goals and the concept of a circular economy.