Journal article
METABOLIC SPATIAL VARIABILITY IN ELECTRODE-RESPIRING GEOBACTER SULFURREDUCENS BIOFILMS
Energy & environmental science, Vol.6(6), pp.1827-1836
06/01/2013
Handle:
https://hdl.handle.net/2376/114275
PMCID: PMC3733395
PMID: 23930138
Abstract
In this study, we quantified electron transfer rates, depth profiles of electron donor, and biofilm structure of
biofilms using an electrochemical-nuclear magnetic resonance microimaging biofilm reactor. Our goal was to determine whether electron donor limitations existed in electron transfer processes of electrode-respiring
biofilms. Cells near the top of the biofilms consumed acetate and were metabolically active; however, acetate concentration decreased to below detection within the top 100 microns of the biofilms. Additionally, porosity in the biofilms fell below 10% near the electrode surface, exacerbating exclusion of acetate from the lower regions. The dense biofilm matrix in the acetate-depleted zone acted as an electrical conduit passing electrons generated at the top of the biofilm to the electrode. To verify the distribution of cell metabolic activity, we used uranium as a redox-active probe for localizing electron transfer activity and X-ray absorption spectroscopy to determine the uranium oxidation state. Cells near the top reduced U
more actively than the cells near the base. High-resolution transmission electron microscopy images showed intact, healthy cells near the top and plasmolyzed cells near the base. Contrary to models proposed in the literature, which hypothesize that cells nearest the electrode surface are the most metabolically active because of a lower electron transfer resistance, our results suggest that electrical resistance through the biofilm does not restrict long-range electron transfer. Cells far from the electrode can respire across metabolically inactive cells, taking advantage of their extracellular infrastructure produced during the initial biofilm formation.
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Details
- Title
- METABOLIC SPATIAL VARIABILITY IN ELECTRODE-RESPIRING GEOBACTER SULFURREDUCENS BIOFILMS
- Creators
- Rs Renslow - The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USAJt BabautaA DohnalkovaMi BoyanovKm KemnerPd MajorsJk FredricksonH Beyenal
- Publication Details
- Energy & environmental science, Vol.6(6), pp.1827-1836
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Publisher
- England
- Grant note
- T32 GM008336 / NIGMS NIH HHS R21 DE017232 / NIDCR NIH HHS
- Identifiers
- 99900547812701842
- Language
- English
- Resource Type
- Journal article