Carbonic anhydrase encapsulation using bamboo cellulose scaffolds for efficient CO capture and conversion.

Utilizing carbonic anhydrase (CA) to catalyze CO hydration offers a sustainable and potent approach for carbon capture and utilization. To enhance CA's reusability and stability for successful industrial applications, enzyme immobilization is essential. In this study, delignified bamboo cellulose served as a renewable porous scaffold for immobilizing CA through oxidation-induced cellulose aldehydation followed by Schiff base linkage. The catalytic performance of the resulting immobilized CA was evaluated using both p-NPA hydrolysis and CO hydration models. Compared to free CA, immobilization onto the bamboo scaffold increased CA's optimal temperature and pH to approximately 45 °C and 9.0, respectively. Post-immobilization, CA activity demonstrated effective retention (>60 %), with larger scaffold sizes (i.e., 8 mm diameter and 5 mm height) positively impacting this aspect, even surpassing the activity of free CA. Furthermore, immobilized CA exhibited sustained reusability and high stability under thermal treatment and pH fluctuation, retaining >80 % activity even after 5 catalytic cycles. When introduced to microalgae culture, the immobilized CA improved biomass production by ∼16 %, accompanied by enhanced synthesis of essential biomolecules in microalgae. Collectively, the facile and green construction of immobilized CA onto bamboo cellulose block demonstrates great potential for the development of various CA-catalyzed CO conversion and utilization technologies.