U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Extracellular Polymeric Substances Stop Migration of Subsurface Contaminants
Published: May 31, 2011
Posted: June 22, 2011

Subsurface uranium is a significant contaminant at U.S. Department of Energy sites. Remediation solutions include immobilizing contaminants to prevent them from reaching groundwater. Using a model organism isolated from a uranium seep of the Columbia River, scientists recently quantified how extracellular polymeric substances (EPS) in subsurface environments can be used to immobilize heavy metal and radionuclide contaminants such as uranium [U(VI)]. In geologic systems, EPS can help bind microbes to mineral surfaces, influence cellular metabolism, and influence the fate and transport of contaminants. Using a novel biofuel reactor designed by scientists from the Environmental Molecular Sciences Laboratory (EMSL), the team prepared biofilms of a Shewanella species that produces EPS, and quantitatively analyzed the contribution of EPS to U(VI) immobilization. Using EMSL’s nuclear magnetic resonance capabilities to analyze chemical residues in EPS samples and cryogenic fluorescence spectroscopy to obtain sensitive U(VI) measurements, they tested the reactivity of loosely associated EPS and bound EPS with U(VI). The scientists found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI) and the bound EPS contributed significantly to its immobilization, primarily through redox-active proteins. For loosely associated EPS, sorption of U(VI) was attributed predominantly to reaction with polysaccharides. These results could lead to the development of improved remediation techniques for subsurface contaminants.

Reference: Cao, B., B. Ahmed, D. W. Kennedy, Z. Wang, L. Shi, M. J. Marshall, J. K. Fredrickson, N. G. Isern, P. D. Majors, and H. Beyenal. 2011. "Contribution of Extracellular Polymeric Substances from Shewanella sp. HRCR-1 Biofilms to U(VI) Immobilization," Environmental Science and Technology, DOI: 10.1021/es200095j. (Reference Link)

Contact: Paul E. Bayer, SC-23.1, (301) 903-5324
Topic Areas:

  • Research Area: Subsurface Biogeochemical Research
  • Research Area: DOE Environmental Molecular Sciences Laboratory (EMSL)
  • Research Area: Microbes and Communities
  • Research Area: Research Technologies and Methodologies

Division: SC-23.1 Climate and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)