Structural study of Carbonic Anhydrases for Bioconsolidation applications

Microbial-induced calcium carbonate precipitation (MICCP) is a naturally occurring biological process in which bacteria promote the production of calcium carbonate, from microscopic crystals to large geological formations. This technology has been extensively explored in various environmentally friendly applications, such as the biorestoration of limestone monuments and carbon sequestration by mineral carbonation (1,2). An important role in the microbially induced calcium carbonate precipitation process is played by carbonic anhydrase (CA), a key enzyme present in all living organisms (3,4,5). This zinc-containing protein, which facilitates the interconversion of CO2 and bicarbonate, has a wide distribution and participates in many physiological processes, such as cellular pH regulation, and acid and ion transport. By analysing the ability to precipitate calcium carbonate crystals, we selected the most suitable bacterial strains for bioconsolidation applications. To gain insights into the structure-function relationships, the CAs of the different isolated strains were identified and classified from the structural point of view. A comprehensive comparative study led to the identification of the structural determinants of CA to select the best calcium carbonate bacterial producers for a wide range of applications.