Mechanisms and optimization Strategies for surfactant-mediated enhancement of enzymatic hydrolysis of Poly(ethylene terephthalate).

Polyethylene terephthalate (PET) pollution has become a worldwide environmental challenge, and enzymatic hydrolysis represents a green and sustainable strategy to address this contamination. To enhance enzymatic PET hydrolysis, this study systematically compared the effects of five common surfactants-sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), di-rhamnolipid (DRL), lauryl betaine (LAB), and polyethylene glycol (PEG300)-on Humicola insolens cutinase (HiC)-catalyzed PET hydrolysis with two different crystallinities. Integrated experimental and computational approaches elucidated the intrinsic mechanism of surfactant-regulated enzymatic PET hydrolysis. Enzymatic hydrolysis results showed that SDS and CTAB inhibit PET hydrolysis, while DRL and LAB slightly enhance it. Notably, 4% (w/v) PEG300 significantly increased the degradation rates of low-crystallinity PET and high-crystallinity PET by 60.23% and 59.28%, respectively, compared with HiC alone. Subsequent studies on surface wettability, enzyme stability, and molecular simulations demonstrated that PEG enhanced enzymatic hydrolysis by regulating the hydrophilicity at the PET interface and the activity and stability of HiC. This study proposes a universal and highly efficient interfacial regulation strategy, laying the foundation for developing enzyme protectants and advancing green and sustainable PET hydrolysis.