Enhanced biomimetic sequestration of CO2 into CaCO3 using purified carbonic anhydrase from indigenous bacterial strains

Phenomenal rise in CO2 concentration have led to disastrous consequences. The present study endeavors the biomimetic sequestration of CO2 into CaCO3 using biological catalyst; carbonic anhydrase (CA) purified from Pseudomonas fragi, Micrococcus lylae and Micrococcus luteus 2 along with a comparative evaluation of their efficiency against commercial bovine carbonic anhydrase (BCA). At pH range 8.0–9.0 and temperature range 35–45 °C, maximum stability was observed for CA from M. luteus 2 followed by P. fragi CA, M. lylae CA and BCA. P. fragi CA demonstrated maximum stability as function of time with respect to pH and temperature. The anionic inhibitors, Cl−, SO42−, NO3−, HCO3 and toxic metal ions viz., lead, arsenic and mercury showed varied inhibitory profile against the four different CAs. The level of inhibition was significantly higher for BCA and M. luteus 2 CA compared to P. fragi CA and M. lylae CA. Calcium estimation was found to be a reliable method for the determination of sequestration efficiency. Indigenous CAs and their consortia exhibited enhanced CO2 sequestration competence compared to commercial BCA. Sequestration efficiency at 45 °C, under process parameters was found to be maximum for CA consortia (61%) and minimum for commercial BCA (17.8%) indicating its potential application in an onsite scrubber.