Sporosarcina pasteurii can form nanoscale calcium carbonate crystals on cell surface

PLoS One. 2019 Jan 30;14(1):e0210339. doi: 10.1371/journal.pone.0210339. eCollection 2019.

Abstract

The bacterium Sporosarcina pasteurii (SP) is known for its ability to cause the phenomenon of microbially induced calcium carbonate precipitation (MICP). We explored bacterial participation in the initial stages of the MICP process at the cellular length scale under two different growth environments (a) liquid culture (b) MICP in a soft agar (0.5%) column. In the liquid culture, ex-situ imaging of the cellular environment indicated that S. pasteurii was facilitating nucleation of nanoscale crystals of calcium carbonate on bacterial cell surface and its growth via ureolysis. During the same period, the meso-scale environment (bulk medium) was found to have overgrown calcium carbonate crystals. The effect of media components (urea, CaCl2), presence of live and dead in the growth medium were explored. The agar column method allows for in-situ visualization of the phenomena, and using this platform, we found conclusive evidence of the bacterial cell surface facilitating formation of nanoscale crystals in the microenvironment. Here also the bulk environment or the meso-scale environment was found to possess overgrown calcium carbonate crystals. Extensive elemental analysis using Energy dispersive X-ray spectroscopy (EDS) and X-ray powder diffraction (XRD), confirmed that the crystals to be calcium carbonate, and two different polymorphs (calcite and vaterite) were identified. Active participation of S. pasteurii cell surface as the site of calcium carbonate precipitation has been shown using EDS elemental mapping with Scanning transmission electron microscopy (STEM) and scanning electron microscopy (SEM).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomineralization
  • Calcium Carbonate / chemistry*
  • Calcium Carbonate / metabolism*
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism
  • Cell Membrane / ultrastructure
  • Crystallization
  • Culture Media
  • Microscopy, Electron, Scanning
  • Microscopy, Electron, Scanning Transmission
  • Nanostructures / chemistry
  • Nanostructures / ultrastructure
  • Powder Diffraction
  • Spectrometry, X-Ray Emission
  • Sporosarcina / growth & development
  • Sporosarcina / metabolism*
  • Sporosarcina / ultrastructure*

Substances

  • Culture Media
  • Calcium Carbonate

Grants and funding

AK acknowledges partial support from NSERC, Canada. AK acknowledges partial support from the Startup Grant provided by the Indian Institute of Science. There were no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.