Catalytically inactive lytic polysaccharide monooxygenase PcAA14A enhances the enzyme-mediated hydrolysis of polyethylene terephthalate.

The massive accumulation of polyethylene terephthalate (PET) in the global ecosystem is a growing environmental crisis. Development of environmental friendly strategies to achieve enzyme–catalyzed PET degradation has attracted tremendous attention. In this study, we demonstrated the synergistic effects of combining a specific PET–degrading enzyme Is PETaseEHA variant from PET–assimilating bacterium Ideonella sakaiensis and a lytic polysaccharide monooxygenase from a white–rot fungus Pycnoporus coccineus (Pc AA14A) in PET degradation. We found that the presence of Pc AA14A alone did not result in PET hydrolysis, but its presence could stimulate Is PETaseEHA–mediated hydrolytic efficiency by up to 1.3-fold. Notably, the stimulatory effects of Pc AA14A on Is PETaseEHA–catalyzed PET hydrolysis were found to be independent of monooxygenase activity. Dose–effects of Is PETaseEHA and Pc AA14A on PET hydrolysis were observed, with the optimal concentrations being determined to 25 μg/mL and 0.25 μg/mL, respectively. In the 5-day PET hydrolysis experiment, 1097 μM hydrolysis products were produced by adding the optimized concentrations of Is PETaseEHA and Pc AA14A, which was 27.7% higher than those were produced by Is PETaseEHA alone. Our study reports the first time that Pc AA14A could stimulate the Is PETaseEHA–mediated PET hydrolysis through a monooxygenase activity independent manner. [ABSTRACT FROM AUTHOR]