Responsive Emulsions Enabled by Supramolecular Polymers for Recyclable Biocatalysis

ABSTRACT Emulsion biocatalysis harnesses liquid–liquid interfaces to facilitate mass transfer for achieving efficient biocatalysis. However, it has been a great challenge in recycling the emulsions in the downstream process. Here, we present a supramolecular approach to design a responsive emulsion for recyclable biocatalysis. Crown ether acrylate monomers are copolymerized with N ‐isopropylacrylamide to yield amphiphilic supramolecular polymer as emulsifiers, which further enable to form robust emulsions, accommodating both isolated enzymes and whole‐cell catalysts and supporting single‐step transformations as well as multi‐enzymatic cascades, with performance that surpasses conventional biphasic systems. Importantly, leveraging the reversible crown‐ether/secondary‐ammonium recognition, the introduction of a complementary dibenzylammonium guest triggers supramolecular cross‐linking, enabling straightforward recovery and reuse of both emulsifier and catalyst with minimal activity loss, and subsequent mild pH modulation de‐complexes the host–guest assembly, resulting in a reversibly switching system between emulsion and two‐phase states. Additionally, Escherichia coli overexpressing BAL retains 80% of its initial activity over three consecutive cycles in this responsive emulsion. Therefore, our findings establish supramolecular polymer–stabilized emulsions as a versatile, recyclable platform for biocatalysis, providing a general strategy that bridges supramolecular polymer design with green chemical synthesis and offering strong potential for sustainable industrial chemical synthesis.