BSBE Seminar丨Dr. Hongyuan LU from University of Texas at Austin
Plastic waste poses an ecological challenge and enzymatic degradation offers a green and sustainable route for plastic waste recycling. Poly (ethylene terephthalate) (PET) accounts for 12% of global solid waste, and a circular carbon economy for PET is theoretically attainable through rapid enzymatic depolymerization followed by repolymerization or valorization into other products. However, the practical application of PET hydrolases has been hampered by their lack of robustness, slow reaction rates and inability to directly use untreated postconsumer plastics.
Herein, we report the use of a structure-based, machine learning algorithm to engineer a robust and active PET hydrolase. Our best resulting mutant (FAST-PETase: Functional, Active, Stable, and Tolerant PETase) exhibits superior PET-hydrolytic activity relative to both wild-type and engineered alternatives. We demonstrate that whole, untreated, post-consumer PET from 51 different plastic products can all be completely degraded by FAST-PETase within one week, and in as little as 24 hours. FAST-PETase can also depolymerize untreated, amorphous portions of a commercial water bottle and an entire thermally pretreated water bottle at 50 ºC. Moreover, we demonstrate a closed-loop PET recycling process by using FAST-PETase and resynthesizing PET from the recovered monomers. Collectively, our results demonstrate a viable route for enzymatic plastic recycling at the industrial scale.