Calcium Carbonate Formation in the Presence of Biopolymeric Additives

Novel method to achieve crystallinity of calcite by Bacillus subtilis in coupled and non-coupled calcium-carbon sources

“…The main components of B. subtilis EPS, that promote calcite aggregation, are TasA and TapA amyloid proteins and exopolysaccharides (Azulay and Chai 2019 ); moreover, there are reports of nanotubes formation when B. subtilis grows in rich media (Bhattacharya et al 2019 ). In this study, both structures were observed in BCC-GLC (Fig.…”

“…Besides, EPS is important to CaCO 3 precipitation (Decho 2010 ; López-Moreno et al 2014 ), because it attract Ca 2+ to its chemical functional groups, such as: COO–, NH 3 –, PO 4 – and SO 4 – groups (Schmitt and Flemming 1998 ; Humbert and Quilès 2011 ). Those group, related to main EPS components (exopolysaccharides and proteins) play a key role in BCC formation (Azulay and Chai 2019 ). P content may be related to extracellular DNA usually present in EPS (Peng et al 2020 ).…”

Counter-Diffusion System as an in Vitro Model in the Investigation of Proteins Involved in the Formation of Calcium Carbonate Biominerals

“…The easiest way to test the effect of an additive on the calcium carbonate crystallization is to use a reactive crystallization by the liquid–liquid reaction method also referred to as the solution method. It based on the process in which supersaturation is achieved by a chemical reaction between two soluble reactantsin the calcium carbonate case by mixing a soluble salt of calcium (e.g., calcium chloride) with a soluble salt of carbonate (e.g., sodium carbonate). − The process may be performed inside a reactor, with three cells that are separated by a porous membrane where calcium and carbonate diffuse from the outer to the middle cell resulting in the precipitation of the less soluble calcium carbonate, or simply by the direct adding and fast mixing of these two solutions. ,, The second approach was used to study, for example, the incorporation of recombinant Perlucin protein, , the effect of recombinant sea urchin spicule matrix protein, rSpSM50, on the calcium carbonate mineralization process, as well as to screen the incorporation of amino acids into the crystalline lattice of calcite . The method is fast and very simple.…”

“…It is based on mineralization occurring in the solution of calcium chloride supplemented with the molecule under investigation. The crystal growth occurs slowly by diffusion of vapor released during a deconvolution of ammonium carbonate into the calcium ion solution bearing an additive in a closed chamber. ,, As one of the most popular techniques, it has been used plenty of times to study the effect of polypeptides on the biomineralization of calcium carbonate. ,,,− This method is easy and relatively fast; however, it has shown some disadvantages such as low reproducibility, difficulty of monitoring, and dependency of the mineralization process upon the volumes of the solution and of the chamber. ,− To overcome these problems, a device named the “crystallization mushroom” was developed, which allows carrying out precipitation experiments by the vapor-diffusion sitting drop technique. This setup offers the advantage of good reproducibility and allows researchers to monitor the experiment in situ using an ion-selective electrode or a pH-electrode and to observe the growing crystals in situ using optical microscopy. , The above method has been used to study the effect of numerous proteins on calcium carbonate mineralization including lysosome, carbonic anhydrase, eggshell matrix protein fractions, and many others.…”

“…15−17 The process may be performed inside a reactor, with three cells that are separated by a porous membrane where calcium and carbonate diffuse from the outer to the middle cell resulting in the precipitation of the less soluble calcium carbonate, or simply by the direct adding and fast mixing of these two solutions. 15,16,18 The second approach was used to study, for example, the incorporation of recombinant Perlucin protein, 19,20 the effect of recombinant sea urchin spicule matrix protein, rSpSM50, on the calcium carbonate mineralization process, 21 as well as to screen the incorporation of amino acids into the crystalline lattice of calcite. 22 The method is fast and very simple.…”