This study evaluates the catalytic efficiency of immobilized carbonic anhydrase (CA) enzymes in dynamic CO2 capture systems using a robust measurement and modeling framework. The experimental setup consists of a two-phase bioreactor where a controlled stream of nitrogen and CO2 (up to 20% concentration) is bubbled into a liquid phase containing either pure water or aqueous solutions with immobilized CA. The system operates at fixed temperatures (25°C and 4°C) with a constant total gas flow of 200 mL/min and liquid circulation of 100 mL/min. Real-time monitoring of pH via an electrochemical probe and CO2 concentration at the outlet using a non-dispersive infrared (NDIR) sensor enables precise tracking of reaction dynamics during transient conditions.
Two distinct methods are employed to induce perturbations: (1) injection of a 1 mL aliquot of 10 mM Tris buffer into the reactor, causing an abrupt shift in proton concentration; and (2) step changes in the inlet CO2 concentration from 0% to 1%, 2%, 5%, or 10%, without altering the total flow rate. These transients generate measurable responses in both pH and gas-phase CO2 levels, allowing for detailed analysis of the system’s recovery kinetics. The focus is on assessing how immobilized CA—specifically thermostable SspCA anchored on Escherichia coli cell surfaces—enhances the rate of CO2 hydration compared to enzyme-free controls.
A mechanistic chemical kinetics model is developed to simulate the time evolution of dissolved CO2, H2CO3, HCO3⁻, and H⁺ concentrations. The model accounts for the reversible reactions involved in CO2 hydration, including the catalytic mechanism mediated by CA, which involves zinc-bound hydroxide attack on CO2 followed by bicarbonate release. The equations are formulated as a system of first-order differential equations, with rate constants estimated through non-linear least squares fitting using MATLAB. To account for instrumental delays, a first-order filter is integrated into the model, representing the effective response time of the measurement system, determined experimentally via reference step tests.2-Nitroterephthalic acid Formula
Results demonstrate that immobilized SspCA significantly accelerates the hydration process.SARS-CoV-2 PLpro Protein Protocol At 25°C, the forward rate constant kf1 increases from ~2.PMID:35219092 2 × 10⁻³ s⁻¹ (no enzyme) to over 12.5 × 10⁻³ s⁻¹ with 20 mg of CA, indicating a more than fivefold enhancement. The reverse rate constant kb1 also rises substantially, confirming increased turnover. Even at low enzyme concentrations (e.g., 10 mg), clear differences in transient recovery times are observed between CA-present and CA-absent runs. At 4°C, although overall reaction rates are reduced due to lower temperature, the relative catalytic advantage remains evident, with the model accurately predicting system behavior despite slightly higher errors in pH estimation (up to 18%).
The proposed method provides a sensitive, repeatable, and physically grounded approach to quantify enzyme performance. By analyzing transient responses rather than relying on endpoint measurements, it avoids common pitfalls such as signal noise amplification in derivative-based analyses. Furthermore, it enables direct extraction of kinetic parameters linked to molecular mechanisms, facilitating comparisons between different CA variants and immobilization strategies. This work validates the use of dynamic modeling in evaluating bio-catalytic systems for environmental applications, particularly in developing efficient, scalable, and sustainable CO2 capture technologies based on enzymatic catalysis.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
