Are Calcite Nanoparticles or Organics Causing Autofluorescence of Microbially Produced Calcium Carbonate Precipitates?
EMSL Project ID
51032
Abstract
Microbially induced mineralization is a broad field of research that investigates the precipitation of minerals induced by the presence or activity of microorganisms. Specifically, Microbially Induced Calcium carbonate Precipitation (MICP) has been demonstrated by us and others to have potential in geotechnical, industrial, energy and environmental applications. We recently developed a droplet microfluidics system, which allows us to study mineral precipitation and microbe-mineral interactions on the single cell-scale. We have successfully (i) observed microbial growth and mineral precipitation non-invasively over time using confocal laser scanning microscopy (CLSM) in microdroplets initially containing single cells, as well as (ii) characterized the resulting precipitates and relationships between precipitates and microbial cells using Raman and Scanning Electron Microscopy (SEM), X-ray diffraction and Nano-Auger analyses. However, as summarized below, it has remained unclear what mineral phases are precipitating and what the role of nano-crystalline phases (hypothesis 1) or organics (hypothesis 2) might be in the observed fluorescence of some of the precipitates.
Hence, our specific aims for this Limited Scope proposal are as follows:
1.) To use SEM and Scanning Transmission Electron Microscopy (STEM) coupled with energy dispersive spectroscopy (EDS) and selected area electron diffraction (SAED) analyses to
a. identify the produced minerals based on morphology, elemental make-up and crystallinity after preparation of thin-sections by focused ion beam milling and/or ultramicrotomy
b. image the spatial relationship between bacterial cells and the precipitated minerals
2.) To use ToF-SIMS and optical microscopy (Confocal and Super Resolution Fluorescence Microscopy) to identify the spatial relationship between minerals and bacteria in the mineral conglomerates as well as to characterize the possible role of organics in the observed fluorescence.
Understanding the role of organics in the process of mineral precipitation and aggregation will ultimately allow us to develop better technologies for sealing leaky wells, stabilize foundations and immobilize hazardous contaminants in the subsurface.
Project Details
Project type
Limited Scope
Start Date
2019-10-21
End Date
2019-12-19
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members