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Updated: May 9, 2026
11:58
Waste Water Derived Electroactive Microbial Biofilms: Growth, Maintenance, and Basic Characterization
Published on: December 29, 2013
METABOLIC SPATIAL VARIABILITY IN ELECTRODE-RESPIRING GEOBACTER SULFURREDUCENS BIOFILMS
Rs Renslow1, Jt Babauta, A Dohnalkova
1The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA.
Energy & Environmental Science
|August 10, 2013
Summary
Electron donor limitation does not restrict electron transfer in Geobacter sulfurreducens biofilms. Even with acetate depletion, dense biofilms facilitate long-range electron transfer via extracellular infrastructure.
Area of Science:
- Microbiology
- Electrochemistry
- Biofilm Engineering
Background:
- Geobacter sulfurreducens is an electrode-respiring bacterium crucial for microbial fuel cells.
- Understanding electron transfer limitations in biofilms is key to optimizing bioelectrochemical systems.
Purpose of the Study:
- To investigate electron donor limitations in Geobacter sulfurreducens biofilms.
- To correlate biofilm structure with electron transfer rates and metabolic activity.
Main Methods:
- Utilized an electrochemical-nuclear magnetic resonance microimaging biofilm reactor.
- Quantified electron donor depth profiles and biofilm porosity.
- Employed uranium as a redox probe and X-ray absorption spectroscopy for metabolic activity mapping.
Main Results:
- Acetate was depleted within 100 microns of the biofilm surface.
- Biofilm porosity decreased significantly near the electrode, hindering acetate diffusion.
- Metabolic activity and cell health decreased with depth, yet long-range electron transfer persisted.
Conclusions:
- Electrical resistance, not donor limitation, is the primary factor for electron transfer in these biofilms.
- Metabolically inactive cells support electron transfer through extracellular matrix.
- Existing models on metabolically active cells at the electrode surface are challenged.
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