Enhancement of the yield of poly (ethylene terephthalate) hydrolase production using cell membrane protection strategy

Biodegradation, particularly via enzymatic degradation, has emerged as an efficient and eco-friendly solution for Poly (ethylene terephthalate) (PET) pollution. The production of PET hydrolases plays a role in the large-scale enzymatic degradation. However, an effective variant, 4Mz, derived from Thermobifida fusca cutinase (Tfu_0883), was previously associated with a significant reduction in yield when compared to the wild-type enzyme. In this study, a novel cell membrane protection strategy was developed to enhance the yield of 4Mz. This approach increased the yield of 4Mz by 18.2-fold from shaken flasks to 3-L bioreactors, reaching a yield of 3.1 g·L −1 , the highest yield of a PET hydrolase described thus far. In addition, the raw culture broth from 4Mz was applied directly for the enzymatic degradation of PET bottles, achieving a 91.2 % degradation rate. These advancements render the large-scale enzymatic degradation of PET more feasible, thus contributing to the more sustainable management of plastic waste.