- Enzymatic carbon capture is an emerging and environmentally friendly approach to capturing carbon dioxide (CO₂) from industrial emissions or the atmosphere using biological catalysts—enzymes—that accelerate chemical reactions involved in CO₂ separation and conversion. This bioinspired method offers several potential advantages over traditional chemical carbon capture techniques, such as lower energy consumption, faster reaction rates, and improved environmental compatibility.
- At the heart of this approach is carbonic anhydrase, a highly efficient natural enzyme that plays a critical role in CO₂ transport and exchange in living organisms. Carbonic anhydrase catalyzes the reversible reaction between CO₂ and water to form bicarbonate ions (HCO₃⁻) and protons (H⁺):
- CO₂ + H₂O ⇌ HCO₃⁻ + H⁺
- This reaction occurs naturally in humans and other organisms to help regulate pH and transport CO₂ in the bloodstream. In enzymatic carbon capture systems, this same reaction is harnessed to rapidly convert CO₂ into bicarbonate in aqueous solutions, greatly enhancing the rate of CO₂ absorption compared to non-catalyzed processes. The bicarbonate can then be precipitated as solid carbonates or processed further, depending on the intended application (e.g., storage or utilization).
- Enzymatic carbon capture can be integrated into post-combustion capture systems, where CO₂ is extracted from flue gas after fossil fuel combustion. Traditional methods often rely on energy-intensive amine solvents, which must be heated to release the captured CO₂—a process that consumes large amounts of energy and contributes to operational costs. Enzyme-assisted systems, by contrast, operate effectively at lower temperatures and can reduce both the energy penalty and corrosive impacts associated with chemical solvents. Some approaches use enzymes embedded in membranes or immobilized on solid supports, enabling continuous CO₂ capture in reactors or flow systems.
- To enhance the practicality of enzymatic carbon capture, significant research is focused on enzyme stability and performance under industrial conditions. Natural carbonic anhydrase is sensitive to heat, pH fluctuations, and harsh chemicals, so scientists are engineering more robust variants through protein engineering, directed evolution, and synthetic biology. Some projects also explore thermophilic enzymes from extremophiles (organisms that live in hot environments), which naturally exhibit greater stability at high temperatures.
- A promising area of development is coupling enzymatic capture with carbon utilization, converting captured CO₂ into valuable products such as biofuels, bioplastics, or building materials. Enzymes can help transform bicarbonate or CO₂ into other molecules through metabolic or catalytic pathways, making the process not only a carbon mitigation strategy but also an economically viable technology for a circular carbon economy.
- Despite its potential, enzymatic carbon capture still faces technical and economic challenges. The cost of enzyme production, scaling up, and maintaining enzyme activity over time are major concerns. However, advancements in biocatalyst production, enzyme immobilization, and hybrid systems combining biological and chemical components are making this technology increasingly feasible for real-world applications.
