Extraction, Purification, and Kinetic Studies of Carbonic Anhydrase fromSpinacia oleracea Leaves and Its Efficiency in CO2 Sequestration

Introduction: To isolate, purify, and characterize CA from a novel source Spinacia oleracea (Spinach), and determine its catalytic efficacy in CO2 sequestration. Methods: The MALDI TOF technique was used to study the molecular mass and protein sequence of the purified enzyme from S. oleracea. A UV-Vis spectrophotometer was used to study the kinetic parameters of the CA enzyme from the source. SEM, FTIR, and XRD were used to analyze the products formed from CO2 sequestration by the CA source. Results: The kinetic parameters Kₘ, Vₘₐₓ, kcat, pH optimum, and temperature optimum of the S. oleracea CA were 0.62 mM, 0.73 µmol/min, 37.3 s-1 , 9.0, and 40℃, respectively. The enzyme was purified 29-fold, with a specific activity of 12.90 U/mg and a recovery of 16.29%. Under optimized conditions, spinach CA was found to be effective in sequestering CO2 into CaCO3, with the highest CO2 sequestration efficacy at pH 10.0, 20℃, and 0.5 M (CaCl2.2H2O). Discussion: The experimental results show that under optimized conditions, the use of spinach CA as a catalyst significantly improved the CO₂ sequestration efficiency by nearly two-fold compared with that of the control. A key limitation of our study is that it was carried out at the laboratory scale, and consequently, additional research is necessary to carry out this work under harsh industrial conditions. Despite this, we can conclude that spinach leaf CA is a viable candidate for CO₂ sequestration, although enzyme immobilization is necessary for improved enzyme stability. Conclusion: This study suggests that spinach leaf CA can be regarded as a potential CA source and a biocatalyst for CO2 sequestration.