Influence of Substrate Mineralogy on Bacterial Mineralization of Calcium Carbonate: Implications for Stone Conservation

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>The influence of mineral substrate composition and structure on bacterial calcium carbonate productivity and polymorph selection was studied. Bacterial calcium carbonate precipitation occurred on calcitic (Iceland spar single crystals, marble, and porous limestone) and silicate (glass coverslips, porous sintered glass, and quartz sandstone) substrates following culturing in liquid medium (M-3P) inoculated with different types of bacteria (<jats:named-content content-type="genus-species">Myxococcus xanthus</jats:named-content>,<jats:named-content content-type="genus-species">Brevundimonas diminuta</jats:named-content>, and a carbonatogenic bacterial community isolated from porous calcarenite stone in a historical building) and direct application of sterile M-3P medium to limestone and sandstone with their own bacterial communities. Field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), powder X-ray diffraction (XRD), and 2-dimensional XRD (2D-XRD) analyses revealed that abundant highly oriented calcite crystals formed homoepitaxially on the calcitic substrates, irrespective of the bacterial type. Conversely, scattered spheroidal vaterite entombing bacterial cells formed on the silicate substrates. These results show that carbonate phase selection is not strain specific and that under equal culture conditions, the substrate type is the overruling factor for calcium carbonate polymorph selection. Furthermore, carbonate productivity is strongly dependent on the mineralogy of the substrate. Calcitic substrates offer a higher affinity for bacterial attachment than silicate substrates, thereby fostering bacterial growth and metabolic activity, resulting in higher production of calcium carbonate cement. Bacterial calcite grows coherently over the calcitic substrate and is therefore more chemically and mechanically stable than metastable vaterite, which formed incoherently on the silicate substrates. The implications of these results for technological applications of bacterial carbonatogenesis, including building stone conservation, are discussed.</jats:p>

The dual role of microbes in corrosion

“…Biologically controlled precipitation is independent of environmental conditions and specific types of minerals are formed depending on the microorganisms (De Muynck et al, 2008). In the case of biologically induced precipitation, the environmental conditions have a large influence, for example, in the case of calcium carbonate production by bacteria, which is determined by calcium concentration, dissolved inorganic carbon concentration, pH and the availability of nucleation sites (De Muynck et al, 2010;Rodriguez-Navarro et al, 2012). Calcium carbonate precipitation by Sporosarcina pasteurii decreased water uptake, permeability and chloride penetration, enhancing the durability of concrete structures (Bang et al, 2010;Achal et al, 2011).…”

Soil bacteria that precipitate calcium carbonate: mechanism and applications of the process

“…Therefore, bound cations (metal ions) react with anions (carbonates) to form insoluble calcium carbonate (De Muynck et al, 2010b). Bacterial cells play a key role in the MICP because, in addition to being used as nucleation sites, they affect the type of mineral that is going to be formed (Douglas & Beveridge, 1998;Rodriguez-Navarro, Jroundi, Schiro, Ruiz-Agudo & Gonzalez-Muñoz, 2012).…”

Cloning, expression and biochemical characterization of aβ-carbonic anhydrase from the soil bacteriumEnterobactersp. B13

“…Bacterial CAs have an essential role in the life cycle of these organisms, as well as in the regulation of calcium carbonate mineralization, at least in some bacterial species. Indeed, CaCO 3 mineralization by bacteria is crucial for soil and ground water remediation, sequestration and capture of atmospheric CO 2 , as well as sand and soil strengthening and consolidation 3 . CAs are encoded by six evalutionary unrelated families, the a, b, g, d, z 4 and Z-CAs…”