Enzyme mediated transformation of CO2 into calcium carbonate using purified microbial carbonic anhydrase

Tanvi Sharma, Abhishek Sharma, Chang lei Xia, Su Shiung Lam, Azmat Ali Khan, Sonam Tripathi, Raj Kumar, Vijai Kumar Gupta, Ashok Kumar Nadda*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


In this study, a bacterial carbonic anhydrase (CA) was purified from Corynebacterium flavescens for the CO2 conversion into CaCO3. The synthesized CaCO3 can be utilized in the papermaking industry as filler material, construction material and in steel industry. Herein, the CA was purified by using a Sephadex G-100 column chromatography having 29.00 kDa molecular mass in SDS-PAGE analysis. The purified CA showed an optimal temperature of 35 °C and pH 7.5. In addition, a kinetic study of CA using p-NPA as substrate showed Vmax (166.66 μmoL/mL/min), Km (5.12 mM), and Kcat (80.56 sec−1) using Lineweaver Burk plot. The major inhibitors of CA activity were Na2+, K+, Mn2+, and Al3+, whereas Zn2+ and Fe2+ slightly enhanced it. The purified CA showed a good efficacy to convert the CO2 into CaCO3 with a total conversion rate of 65.05 mg CaCO3/mg of protein. In silico analysis suggested that the purified CA has conserved Zn2+ coordinating residues such as His 111, His 113, and His 130 in the active site center. Further analysis of the CO2 binding site showed conserved residues such as Val 132, Val 142, Leu 196, Thr 197, and Val 205. However, a substitution has been observed where Trp 208 of its closest structural homolog T. ammonificans CA is replaced with Arg 207 of C. flavescens. The presence of a hydrophilic mutation in the CO2 binding hydrophobic region is a further subject of investigation.

Original languageEnglish
Article number113538
JournalEnvironmental Research
Issue numberPt D
Early online date28 May 2022
Publication statusPrint publication - Sept 2022

Bibliographical note

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  • CaCO
  • Carbonic anhydrase
  • CO conversion
  • In silico
  • Purification
  • Temperature
  • Electrophoresis, Polyacrylamide Gel
  • Carbon Dioxide/chemistry
  • Calcium Carbonate
  • Carbonic Anhydrases/chemistry


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