Tailored Covalent Organic Frameworks Enable the Encapsulation of Living Cells to Produce Rare Ginsenoside

ABSTRACT

Whole‐cell catalysis holds great potential in the production of rare ginsenoside compound K (CK), but it is limited by poor mass transfer and inadequate stability in practice. Herein, we report a scalable whole‐cell immobilization platform through in situ assembly of recombinant Escherichia coli expressing Sulfolobus solfataricus β‐glycosidase with three covalent organic frameworks (COFs: TpPa, TpBD, and TpTAP) in phosphate‐buffered saline. As demonstrated with TpBD, 18.6 grams of TpBD COF could be synthesized in one pot at room‐temperature. The COF shell uniformly encapsulated the cell surface, yielding a robust biocatalyst with high catalytic efficiency, enhanced stability, and excellent recyclability. Specifically, E. coli @TpBD‐2 showed 1.98‐fold higher catalytic efficiency than free E. coli , while the COF shell significantly improved the E. coli ’s tolerance to industrially relevant harsh conditions. Notably, the scale‐up synthesis in continuous‐flow reactors using abundant ginsenoside Rb1 as substrate afforded a space‐time yield of 0.67 g·L ⁻¹ ·d ⁻¹ for CK at 70°C, with 75.25% initial conversion rate retained after 10 h of continuous operation. Additionally, this platform enabled the immobilization of various prokaryotic and eukaryotic microbes, demonstrating favorable universality. This work establishes a versatile platform for engineering stable whole‐cell biocatalysts, which is beneficial for facilitating the industrialization of biocatalysis.