Robust Biocatalysts Displayed on Crystalline Protein-Layered Cells for Efficient and Sustainable Hydration of Carbon Dioxide

Abstract

Mineral carbonation is the most effective carbon capture technique, but carbon dioxide (CO2) conversion is limited by the slow hydration rate of CO2 (<10(-1) s(-1)). A biological solution exists: carbonic anhydrase (CA) efficiently hydrates CO2 at a turnover rate of approximate to 10(6) s(-1) under ambient conditions, making it an extremely attractive candidate for industrial post-combustion CO2 capture. However, high cost and poor long-term stability impose a technical barrier to its practical uses. Here, a genetically engineered Corynebacterium glutamicum (C. glutamicum) is introduced as a robust cell display platform for the in situ stabilization and low-cost production of CA. The enzyme is displayed in the mycolic layer with porin B as an anchoring protein with (GGGGS)(2) as a spacer. The cell-displayed CA exhibits no significant inactivation of the CO2 hydration activity for at least one month at 37 degrees C. Its denaturation rate constant at 50 degrees C (0.07) is an order of magnitude lower than that of free CA (0.52-0.54). This study demonstrates that a structurally robust cell template allows the effective stabilization of CA, suggesting the C. glutamicum-based cell display as a promising technique to achieve highly efficient, sustainable, and low-cost CO2 capture for industrial applications.