Effect of Doping with Metals, Silicate, And Phosphate Ions on Fluorescence Properties and Morphology of Calcite Single Crystals Synthesized in Geobacillus thermoglucosidasius Parent Colonies
Rie Murai and Naoto Yoshida*
Department of Biochemistry and Applied Biosciences, University of Miyazaki, 1-1 Gakuen Kibanadai-Nishi, Miyazaki, Japan
- *Corresponding Author:
- Naoto Yoshida
Department of Biochemistry and Applied Biosciences
University of Miyazaki, 1-1 Gakuen Kibanadai-Nishi
E-mail: [email protected]
Received Date: February 01, 2016 Accepted Date: February 15, 2016 Published Date: February 22, 2016
Citation: Murai R, Yoshida N (2016) Effect of Doping with Metals, Silicate, And Phosphate Ions on Fluorescence Properties and Morphology of Calcite Single Crystals Synthesized in Geobacillus thermoglucosidasius Parent Colonies. J Microb Biochem Technol 8:100-106. doi: 10.4172/1948-5948.1000270
Copyright: © 2016 Murai R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Geobacillus thermoglucosidasius cells grown on nutrient agar medium (parent colony) were placed on the surface of a calcite-promoting hydrogel containing acetate and calcium. After incubation at 60°C for 4 days, calcite single crystals of 110-130 μm in diameter were synthesized within the parent colony. The calcite contained 6.6% (atom%) Mg and showed striking fluorescent properties. Changes in the morphology and development of fluorescence intensity of calcite synthesized on calcite-promoting hydrogel doped with different metal ions, silicate ion, and phosphate ion were investigated. Doping with Mg, P, or Sr ions yielded calcite lattices with the respective metal ions substitutionally dissolved into calcium sites. On calcite-promoting hydrogel containing 2 mM Mg ion, the calcite Mg content increased to 22 atom%. Doping of the hydrogel with Al, Si, or P ions yielded calcites with increased fluorescence intensity (190-196% of that of control calcites). Contrary to expectations, doping of the hydrogel with Mn, Sr, Fe, or Co ions yielded calcites with decreased fluorescence intensity (64.4-96.9% of that of control calcites). When the hydrogel was doped with Mg or P ions, the calcite surface became smooth or sheet-like, respectively, in contrast to the rough-surfaced spherical morphology of control calcites. Distinctive crevice structures were observed on the surfaces of calcites synthesized on hydrogel doped with Mn or Al ions. Fluorescence microscopy showed that calcites emitted blue, green, or red fluorescence when illuminated with light at wavelengths of 360-370, 460- 500, or 530-560 nm, respectively. Calcites synthesized on hydrogel doped with Al, Si, and P ions emitted stronger fluorescence than control calcites when illuminated with light at 360-370 nm. Our studies have demonstrated that G. thermoglucosidasius is useful for the preparation of calcite phosphors in the absence of rare earth elements.