Calcium carbonates: induced biomineralization with controlled macromorphology
- 1Institute of Microbiology, Friedrich Schiller University Jena, Neugasse 25, 07743 Jena, Germany
- 2Institute of Geosciences, Analytical Mineralogy, Friedrich Schiller University Jena, Carl-Zeiss-Promenade 10, 07745 Jena, Germany
- 3Institute of Geosciences, General & Applied Mineralogy, Friedrich Schiller University Jena, Carl-Zeiss-Promenade 10, 07745 Jena, Germany
- 4Institute of Geosciences, Applied Geology, Friedrich Schiller University Jena, Burgweg 11, 07749 Jena, Germany
Abstract. Biomineralization of (magnesium) calcite and vaterite by bacterial isolates has been known for quite some time. However, the extracellular precipitation has hardly ever been linked to different morphologies of the minerals that are observed. Here, isolates from limestone-associated groundwater, rock and soil were shown to form calcite, magnesium calcite or vaterite. More than 92 % of isolates were indeed able to form carbonates, while abiotic controls failed to form minerals. The crystal morphologies varied, including rhombohedra, prisms and pyramid-like macromorphologies. Different conditions like varying temperature, pH or media components, but also cocultivation to test for collaborative effects of sympatric bacteria, were used to differentiate between mechanisms of calcium carbonate formation. Single crystallites were cemented with bacterial cells; these may have served as nucleation sites by providing a basic pH at short distance from the cells. A calculation of potential calcite formation of up to 2 g L−1 of solution made it possible to link the microbial activity to geological processes.