Background on Microbial Fuel Cells

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Background on Microbial Fuel Cells

• A bio-electric system
• Microbially maintained ion gradient fuels
  electron flow, generating electricity
• Two phases of microbial fuel cells
• Degradation of organic matter (cellulose)
• Electricity generation (transfers ions)

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Examples of Microbial Fuel Cells
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Background on MFCs

• Mixed Cultured MFCs
• Advantages
• Full, robust utilization of breakdown products
• Wide range of functionality
• Single Strain MFCs
• Advantages
• Simplification of bio-component MFC
• Better capacity for genetic engineering in MFCs

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Simultaneous Cellulose Degradation and
Electricity Production by Enterobacter cloacae in
a Microbial Fuel Cell

• Authors Farzaneh Rezaei, Defeng Xing, Rachel
  Wagner, John M. Regan, Tom L. Richard, and Bruce
  E. Logan
• Penn State University

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Methods

• Isolation by DTE (dilution to extinction)
• Based on exoelectrogenartion and cellulose
  degradation
• PCR (polymerase chain reaction), DGGE (denaturing
  gradient gel electrophoresis), and 16S rRNA
  sequence comparison
• Biochemical comparison
• Measured growth with various carbon sources

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Results

• DGGE of dilution to extinction

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Results

• Enterobacter cloacae
• Gram-negative
• Facultative anaerobe
• Rod-shaped
• Motile by peritrichous flagella

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Discussion

• Enterobacter cloacae MFC is first single strained
  MFC.
• This MFC is limited by complete metabolism and
  toxin accumulation.
• Measuring exoelectrogeneration potential by
  Fe(III) reduction is flawed
• Synergistic effects of mixed culture MFCs are
  poorly understood

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Comparison of electricity production
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Critique

• Single wastewater source
• One source limits the potential microbes.
• Researchers should have isolated microbes from
  several sources.
• Isolation and characterization was narrow
• Other microbes from mixed cultures should have
  been examined closely to understand the
  mechanisms behind mixed culture synergy.

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References

• Christy, A. D., 2008. Cellulose Conversion to
  Electricity in Microbial Fuel Cells Challenges
  and Constraints. Microbial Fuel Cells First
  International Symposium
• Rezaei, Farzaneh, et al. 2009. Simultaneous
  cellulose degradation and electricity production
  by Enterobacter cloacae in a Microbial Fuel Cell.
  Appl. Environ. Microbiol. 7536733678
• Zuo, Y., et. al. 2008. Isolation of the
  exoelectrogenic bacterium Ochrobactrum anthropi
  YZ-1 by using a U-tube microbial fuel cell. Appl.
  Environ. Microbiol. 743130-3137

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Questions?