Aqueous Micellar Two-Phase Emulsions: An Integrated Reaction–Separation Platform for Sustainable Enzymatic Depolymerization of PET Waste

Enzymatic depolymerization of plastic waste represents a sustainable route toward monomer recovery for closed-loop recycling, yet its efficiency is hindered by poor enzyme accessibility to hydrophobic polymer surfaces and product inhibition. Here, we develop aqueous micellar two-phase emulsions (AMTPEs), formed by self-assembly of nonionic surfactants and polysaccharides, as an integrated catalytic and separation platform for enhanced enzymatic degradation of poly(ethylene terephthalate) (PET). These AMTPEs exhibit excellent stability and efficient co-encapsulation of PET substrates and hydrolases, via a synergistic “wetting-encapsulation” mechanism. The enzyme's affinity for the substrate was greatly increased, likely due to the dynamic microenvironment in the system. Meanwhile, the continuous polysaccharide phase enables simultaneous product removal to overcome the inhibition of products. The optimized Tween 80/Dex AMTPE system exhibits broad applicability across diverse PET hydrolases, boosting MHET production by 7.7-fold (FsC), 20.8-fold (Fast-PETase), and 15.0-fold (LCC) increases over buffer controls within 24   hours. Moreover, after four catalytic cycles that including the product recovery process, system still retained 92.6% of initial MHET production. This work establishes AMTPEs as an integrated and recyclable platform, thereby addressing the effectively addressing the inherent limitations of traditional PET biodegradation.