Journal article
pH, redox potential and local biofilm potential microenvironments within Geobacter sulfurreducens biofilms and their roles in electron transfer
Biotechnology and bioengineering, Vol.109(10), pp.2651-2662
10/2012
Handle:
https://hdl.handle.net/2376/107955
PMCID: PMC3551578
PMID: 22549331
Abstract
The limitation of pH inside electrode‐respiring biofilms is a well‐known concept. However, little is known about how pH and redox potential are affected by increasing current inside biofilms respiring on electrodes. Quantifying the variations in pH and redox potential with increasing current is needed to determine how electron transfer is tied to proton transfer within the biofilm. In this research, we quantified pH and redox potential variations in electrode‐respiring Geobacter sulfurreducens biofilms as a function of respiration rates, measured as current. We also characterized pH and redox potential at the counter electrode. We concluded that (1) pH continued to decrease in the biofilm through different growth phases, showing that the pH is not always a limiting factor in a biofilm and (2) decreasing pH and increasing redox potential at the biofilm electrode were associated only with the biofilm, demonstrating that G. sulfurreducens biofilms respire in a unique internal environment. Redox potential inside the biofilm was also compared to the local biofilm potential measured by a graphite microelectrode, where the tip of the microelectrode was allowed to acclimatize inside the biofilm. Biotechnol. Bioeng. 2012; 109: 2651–2662. © 2012 Wiley Periodicals, Inc.
The pH continues to decrease in the biofilm through different growth phases, showing that the pH is not always a limiting factor in the biofilm. The local biofilm potential value corresponds to the open circuit potential of graphite electrodes with attached G. sulfurreducens biofilms. Limitations on pH are imposed at the counter electrode surface as current increases. For the first time, the authors measured pH variations at the counter electrode and showed this directly.
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Details
- Title
- pH, redox potential and local biofilm potential microenvironments within Geobacter sulfurreducens biofilms and their roles in electron transfer
- Creators
- Jerome T BabautaHung Duc NguyenTimothy D HarringtonRyan RenslowHaluk Beyenal
- Publication Details
- Biotechnology and bioengineering, Vol.109(10), pp.2651-2662
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Publisher
- Wiley Subscription Services, Inc., A Wiley Company; Hoboken
- Number of pages
- 12
- Grant note
- U.S. Office of Naval Research (ONR) (N00014‐09‐1‐0090)
- Identifiers
- 99900547278401842
- Language
- English
- Resource Type
- Journal article