(245f) First-Principles Understanding of Carbonic Anhydrase’s Role in Enhancing Carbon Capture

Amine-based solvents are widely used for carbon dioxide (CO₂) capture, but they often suffer from high reclamation energy requirements, thermal and oxidative degradation, and environmental concerns.^1,2 These limitations have prompted interest in biomimetic systems, particularly those inspired by the enzymatic carbonic anhydrase (CA). The active site of CA consists of a transition metal, such as Co²⁺, Ni²⁺, Cu²⁺, or Zn²⁺, coordinated by three histidine residues and one water molecule, enabling rapid interconversion between CO₂ and bicarbonate. Under ideal conditions, a single CA enzyme can catalyze up to 10⁶ CO₂ molecules per second, about 4000 times more efficient than monoethanolamine (MEA) while requiring significantly less energy.^3,4 However, their industrial application is still limited by limited thermal stability and poor understanding of the underlying mechanisms.

It has been proposed that CO₂ is captured via a direct reaction between Zn²⁺-bound OH⁻ and CO₂ to form bicarbonate.^5–7 However, it does not fully account for bicarbonate liberation or the role of surrounding solvent molecules, particularly in sterically constrained environments. These limitations highlight the need to explore alternative mechanistic pathways that may better reflect conditions in engineered systems. In this talk, we will present our recent computational studies on the molecular mechanisms responsible for CO₂ capture enhanced by CA enzyme. We employ a multiscale computational framework, including ab initio molecular dynamics (AIMD) with enhanced metadynamics sampling as well as MD simulations with neural network potentials (NNPs), to investigate the key factors governing CA-mediated carbon capture processes.

By performing AIMD simulations combined with metadynamics sampling, we predict free-energy barriers for key reaction steps of possible CO₂ capture pathways and identify a more kinetically favorable route under operating conditions. To extend the accessible simulation timescales, we developed an NNP, which enables investigation of proton and hydroxide transport dynamics in the CA-mediated system over longer timescales. We additionally perform all-atomic classical MD simulations combined with metadynamics sampling to study the CAs of interest, with a particular focus on the transport of relevant species into the catalytic site and analyze the solvation structures. This study provides mechanistic insights to guide the design of next-generation cost-effective solvents for CO₂ capture and also highlights the effectiveness of machine learning-driven interatomic potentials in describing complex solution reactions.

References

(1) Davy, R.; Shanks, R. A.; Periasamy, S.; Gustafason, M. P.; Zambergs, B. M. Development of High Stability Catalysts to Facilitate CO2 Capture into Water–An Alternative to Monoethanolamine and Amine Solvents. Energy Procedia 2011, 4, 1691–1698. https://doi.org/10.1016/j.egypro.2011.02.042.

(2) Stowe, H. M.; Hwang, G. S. Fundamental Understanding of CO2 Capture and Regeneration in Aqueous Amines from First-Principles Studies: Recent Progress and Remaining Challenges. Industrial & Engineering Chemistry Research2017, 56 (24), 6887–6899.

(3) Alvizo, O.; Nguyen, L. J.; Savile, C. K.; Bresson, J. A.; Lakhapatri, S. L.; Solis, E. O. P.; Fox, R. J.; Broering, J. M.; Benoit, M. R.; Zimmerman, S. A.; Novick, S. J.; Liang, J.; Lalonde, J. J. Directed Evolution of an Ultrastable Carbonic Anhydrase for Highly Efficient Carbon Capture from Flue Gas. Proc. Natl. Acad. Sci. U.S.A. 2014, 111 (46), 16436–16441. https://doi.org/10.1073/pnas.1411461111.

(4) Alvizo, O.; Nguyen, L. J.; Savile, C. K.; Bresson, J. A.; Lakhapatri, S. L.; Solis, E. O. P.; Fox, R. J.; Broering, J. M.; Benoit, M. R.; Zimmerman, S. A.; Novick, S. J.; Liang, J.; Lalonde, J. J. Directed Evolution of an Ultrastable Carbonic Anhydrase for Highly Efficient Carbon Capture from Flue Gas. Proc. Natl. Acad. Sci. U.S.A. 2014, 111 (46), 16436–16441. https://doi.org/10.1073/pnas.1411461111.

(5) Shams Ghamsary, M.; Ghiasi, M.; Naghavi, S. S. Insight into the Activation Mechanism of Carbonic Anhydrase( ii) through 2-(2-Aminoethyl)-Pyridine: A Promising Pathway for Enhanced Enzymatic Activity. Phys. Chem. Chem. Phys.2024, 26 (13), 10382–10391. https://doi.org/10.1039/D3CP05687B.

(6) Huang, Y.; Zhang, S.; Chen, H.; Zhao, L.; Zhang, Z.; Cheng, P.; Chen, Y. A Zinc Coordination Complex Mimicking Carbonic Anhydrase for CO₂ Hydrolysis and Sequestration. Inorg. Chem. 2019, 58 (15), 9916–9921. https://doi.org/10.1021/acs.inorgchem.9b01059.

(7) Shao, P.; Ye, J.; Shen, Y.; Zhang, S.; Zhao, J. Recent Advancements in Carbonic Anhydrase for CO2 Capture: A Mini Review. Gas Science and Engineering 2024, 123, 205237. https://doi.org/10.1016/j.jgsce.2024.205237.