Uncovering the dynamics of urease and carbonic anhydrase genes in ureolysis, carbon dioxide hydration and calcium carbonate precipitation

Date

2024-01

Authors

Saracho, Alexandra Clarà
Marek, Ewa J.

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Volume Title

Publisher

Environmental Science and Technology

Abstract

The hydration of CO2 suffers from kinetic inefficiencies that make its natural trapping impractically sluggish. However, CO2-fixing carbonic anhydrases remarkably accelerate its equilibration by six orders of magnitude and are, therefore, ’ideal’ catalysts. Notably, carbonic anhydrase has been detected in ureolytic bacteria, suggesting its potential involvement in microbial induced carbonate precipitation (MICP), yet the dynamics of the urease (Ur) and carbonic anhydrase (CA) genes remain poorly understood. Here, through the use of ureolytic bacterium Sporosaracina pasteurii, we investigate the differing role of Ur and CA in ureolysis, CO2 hydration, and CaCO3 precipitation with increasing CO2(g) concentrations. We show that Ur gene up-regulation coincides with an increase in [HCO3-] following the hydration of CO2 to HCO3- by CA. Hence, CA physiologically promotes buffering, which enhances solubility trapping and affects the phase of the CaCO3 mineral formed. Understanding the role of CO2 hydration on the performance of ureolysis and CaCO3 precipitation provides essential new insights, required for the development of next-generation bio-catalysed CO2 trapping technologies.

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Citation

Saracho, A.C., & Marek, E.J. (2024). Uncovering the dynamics of urease and carbonic anhydrase genes in ureolysis, carbon dioxide hydration and calcium carbonate precipitation. Environmental Science and Technology. https://doi.org/10.1021/acs.est.3c06617