Catalytic Biomineralization of Fluorescent Calcite by the Thermophilic Bacterium Geobacillus thermoglucosidasius

Abstract

The thermophilic Geobacillus bacterium catalyzed the formation of 100-m hexagonal crystals at 60°C in a hydrogel containing sodium acetate, calcium chloride, and magnesium sulfate. Under fluorescence microscopy, crystals fluoresced upon excitation at 365 ؎ 5, 480 ؎ 20, or 545 ؎ 15 nm. X-ray diffraction indicated that the crystals were magnesium-calcite in calcite-type calcium carbonate.

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

“…The authors observed similar effects in the case of calcium carbonate precipitation on concrete mediated by the same ureolytic bacteria (15). Although they provided no explanation for the change in the morphology (and phase) of bacterial precipitates, it could be argued that acetate ions, acting as an additional carbonyl carbon source (93), can lead to higher bacterial activity, EPS production, and supersaturation. High supersaturation and abundant organics may, in turn, kinetically favor vaterite precipitation, as discussed above.…”

“…It has been reported that bacterial attachment to solid substrates has a significant impact on bacterial resistance to physicochemical stressors (93) and enhances bacterial metabolic activity and growth (36,52). Manini and Luna (55) reported that bacterial heterotrophic production is enhanced in calcite microcosms and is reduced in quartz microcosms by using marine bacteria.…”

“…A plausible link of calcium carbonate production to Bacillus subtilis genes, which may suggest that bacterial precipitation of these minerals brings some evolutionary advantage to the microorganisms, has been reported (3). For instance, calcium carbonate precipitation may help fixate excess/ toxic Ca (60) or may help bacteria to survive unfavorable conditions in a cryptobiotic state (93). Nonetheless, viability of calcified bacterial cells for extended periods (more than 1 year) has yet to be demonstrated (94).…”

“…Bacterial mineralization of calcium carbonates has found applications in the remediation (fixation) of metalcontaminated soil and groundwater (87), atmospheric CO 2 sequestration (21,59), the strengthening and consolidation of soil and sand (14), the reduction of the porosity and/or permeability of geological formations (24,29), the protection and repair of concrete and cement structures (15,66), and the conservation of building stone and statuary (16,19,30,38,39,40,47,69,84,88,94). Recently, bacterial precipitation of fluorescent calcium carbonate, with potential applications as a filler in rubber, plastics, and stationery ink and as a fluorescent marker, has been reported (93).…”

Augmented Topological Descriptors of Pore Networks for Material Science

“…Biomineralization refers to the synthesis of inorganic mineral-like materials by living organisms through the combination of chemical elements and such organisms in the same system. Bacteria can form inorganic crystals either intracellularly or extracellularly [24], generating by-products, such as the precipitation of calcium carbonate, as shown in Fig. 1.…”