A Hydrolase with Synergistic Dual-cavity Remodeling for High-efficiency Degradation of PET Waste

Poly(ethylene terephthalate) (PET), a widely used polyester plastic, causes pollution as its resistance to natural degradation. Cost-effective and fast biodegradation of PET waste requires robust engineered enzymes. While Tryptophan 155 (W155) in PET hydrolase (PETase) is crucial for PET interaction, its direct mutagenesis often reduces activity. Previous efforts indirectly modulated W155 via residue 183, but with limited efficacy. Here, we engineered NovaPETase, a synergistic double mutant at residues 155 and 183. The mutant breaks the theoretical constraint of W155 conservation, and at the same time causes its residue 155 shifting from the conventional substrate-restricting C-type conformation to an unrestrictive B-type conformation. Remarkably, NovaPETase achieved 90% degradation of post-consumer bottle-derived PET within just 1.87   hours, reaching near-complete degradation within 2.5   hours. Moreover, it accomplished over 90% degradation of light-colored textile PET waste in only 2.83   hours—representing the first report of an industrial-scale enzymatic process for efficient depolymerization of textile-based PET waste. Furthermore, NovaPETase exhibits broad adaptability to various temperatures, enzyme loadings, and substrate loadings, demonstrating significant potential for reducing operational costs and enhancing efficiency in industrial-scale enzymatic PET waste degradation. In summary, our findings represent a significant advance in understanding and designing industrially applicable polyester hydrolases.