Computational redesign of a hydrolase for nearly complete PET depolymerization at industrially relevant high-solids loading

Abstract

Biotechnological plastic recycling has emerged as a suitable option for addressing the pollution crisis. A major breakthrough in the biodegradation of poly(ethylene terephthalate) (PET) is achieved by using a LCC variant, which permits 90% conversion at an industrial level. Despite the achievements, its applications have been hampered by the remaining 10% of nonbiodegradable PET. Herein, we address current challenges by employing a computational strategy to engineer a hydrolase from the bacterium HR29. The redesigned variant, TurboPETase, outperforms other well-known PET hydrolases. Nearly complete depolymerization is accomplished in 8 h at a solids loading of 200 g kg⁻¹. Kinetic and structural analysis suggest that the improved performance may be attributed to a more flexible PET-binding groove that facilitates the targeting of more specific attack sites. Collectively, our results constitute a significant advance in understanding and engineering of industrially applicable polyester hydrolases, and provide guidance for further efforts on other polymer types.

The application of the LCC variant of polyethylene terephthalate (PET) hydrolase for industrial degradation of PET has been hindered by the 10% of nonbiodegradable PET. Here, the authors use a computational strategy to engineer TurboPETase which outperforms other PETase variants and achieves nearly complete depolymerization of the postconsumer PET bottles at a high, industrially relevant, level of solids loading.