Cloning and expression of gamma carbonic anhydrase from Serratia sp. ISTD04 for sequestration of carbon dioxide and formation of calcite

• Microbial community of marble mine was enriched and characterized.
• Carbonic anhydrase (CA) gene of Serratia sp. was cloned.
• CA enzyme was characterized.
• Gamma carbonic anhydrase was reported homologous to archae and methanogens.
• Use of carbonic anhydrase enzyme for the sequestration of atmospheric CO2.

Bacterial strains isolated from marble mines rock and enriched in the chemostat culture with different concentrations of sodium bicarbonate. The enriched consortium had six bacterial isolates. One of bacterium isolate showed carbonic anhydrase (CA) activity by catalyzing the reversible hydration reaction of carbon dioxide to bicarbonate. The bacterium was identified as Serratia sp. by 16S rRNA sequence analysis. The carbonic anhydrase gene from Serratia sp. was found to be homologous with gamma carbonic anhydrase. The carbonic anhydrase gene was cloned in PET21b(+) and expressed it in recombinant Escherichia coli BL21 (DE3) with His-tag at the C-terminus. The recombinant protein was purified efficiently by using one-step nickel affinity chromatography. Expected size of carbonic anhydrase was approximately 29 kDa in SDS–PAGE gel. Recombinant carbonic anhydrase enzyme was used for biomineralization-based conversion of atmospheric CO2 into valuable calcite minerals. The calcification was confirmed by using XRD, FTIR, EDX and SEM analysis.