Marine bacterial biocalcification and its applications

Biologically induced calcium carbonate (CaCO3) precipitation in the marine environment plays an important role in the biogeochemical carbon cycle. This biocalcification is governed by four key factors: the level of dissolved inorganic carbon on which the level of carbonates (CO32-) in the system depends, the level of calcium ions (Ca2+), the pH and the availability of nucleation sites, i.e., areas of primary crystallisation of the mineral solid phase. The bacteria involved in marine biocalcification will then act on one or more of these factors. This natural process, which occurs in a variety of geological settings, can be mimicked to develop a number of technologies for the sequestration of heavy metals, the protection of metals against corrosion, the restoration and reinforcement of pre-existing materials and the consolidation of granular materials. This study reviews the different microbial metabolic activities leading to the precipitation of CaCO3 and their potential applications in the marine environment.