Protein inorganic hybrid nanoflowers of a microbial carbonic anhydrase as efficient tool for the conversion of CO2 into value added product

BACKGROUND Carbonic anhydrase (CA) is one of the most widely distributed enzymes among plants, animals, and microorganisms, and it has an enormous ability to capture carbon dioxide (CO2). However, the real‐time application of CA is still a challenge due to its low operational stability, its difficulty in recovery from the reaction medium, and its poor durability. RESULTS The synthesis of insoluble protein inorganic hybrid structures at nanoscale was proven as quite useful to catalyze enzymatic biotransformation. Here, CA nanoflowers (CANF) were synthesized with the self‐assembly of metal phosphate and CA. The synthesis of CANF was performed using 0.2 mg mL−1 protein and 2.0 mM CuSO4 at 4 °C under mild shaking conditions. The CANF exhibited optimum activity at pH 7.5 and a temperature of 40°C. The synthesized CANF were used for CO2 conversion under optimized conditions and their kinetic parameters were studied using p‐NPA hydrolysis. The Vmax and Km of CANF were 185.18 μmol min−1 mL−1 and 4.72 mM, compared with those of free CA, 166.66 μmol min−1 mL−1 and 5.12 mM, respectively. The stability of CANF has improved remarkably. The CANF made of metal ions and protein showed higher stability and enzyme activity than free enzymes. Furthermore, the CANF showed good reusability due to their mechanical properties and monodispersity. The production of CaCO3 by CANF was 1.71‐fold higher than that by free CA. CONCLUSION The newly formed CANF showed flower‐like morphology with good catalytic activity. This study demonstrated that CANF technology has a bright future in the conversion of CO2 into CaCO3. © 2023 Society of Chemical Industry (SCI).