Related Experiment Video
Updated: Jun 29, 2025
09:04
Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii
Published on: April 16, 2016
21.9K
Enhanced Strontium Removal through Microbially Induced Carbonate Precipitation by Indigenous Ureolytic Bacteria
Matthew White-Pettigrew1,2, Samuel Shaw1, Lewis Hughes1
1Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, United Kingdom.
ACS Earth & Space Chemistry
|March 27, 2024
Summary
Microbial ureolysis effectively removes strontium (Sr2+) by promoting calcium carbonate precipitation in contaminated sediments. This process, enhanced by biostimulation, aids in immobilizing radioactive strontium (90Sr) and other metals.
Area of Science:
- Environmental Microbiology
- Geochemistry
- Bioremediation
Background:
- Groundwater contamination by strontium (Sr2+), particularly radioactive 90Sr at nuclear sites like Sellafield, poses significant environmental challenges.
- Microbial ureolysis, the breakdown of urea by bacteria, generates alkalinity (NH4+ and HCO3-), which can precipitate metals as carbonates.
- Understanding indigenous microbial potential for strontium removal is crucial for developing effective remediation strategies.
Purpose of the Study:
- To investigate the efficacy of microbial ureolysis for strontium removal from Sellafield-representative sediments.
- To assess the impact of biostimulation agents on enhancing ureolysis and strontium carbonate precipitation.
- To identify key microbial players and mechanisms involved in strontium immobilization.
Main Methods:
- Sediment microcosm studies using indigenous bacteria from Sellafield.
- Urea addition to stimulate ureolysis and carbonate precipitation, with and without biostimulants (acetate/lactate, Fe(III), yeast extract).
- Analysis using environmental scanning electron microscopy (ESEM), Sr K-edge X-ray absorption spectroscopy, and 16S rRNA gene sequencing.
Main Results:
- Urea addition significantly increased pH and enhanced strontium removal in most sediments.
- Biostimulation further augmented ureolysis, leading to increased strontium and calcium removal.
- Spectroscopic and microscopic analyses confirmed strontium incorporation into calcium carbonate polymorphs (calcite and vaterite), with *Sporosarcina* identified as key ureolytic bacteria.
Conclusions:
- Microbial ureolysis is a viable strategy for immobilizing strontium (Sr2+) in contaminated sediments via calcium carbonate co-precipitation.
- Biostimulation can enhance the efficiency of this bioremediation process.
- Ureolysis may also facilitate the reductive precipitation of other redox-active radionuclides, broadening its applicability in nuclear site remediation.
