Microbial fuel cells (MFCs) use bacteria to convert chemical energy from bio-convertible substrates like glucose or acetate directly into electricity. A typical MFC consists of an anode compartment where microbes oxidize fuel and generate electrons and protons, and a cathode compartment exposed to air. A cation-specific membrane allows proton passage between compartments. MFCs offer unlimited fuel sources without pollution and can achieve higher energy conversion than other methods, with no moving parts or noise. Examples demonstrate various microbes generating voltages between 250-650mV using different substrates and mediators or mediator-less systems. Significant factors that affect MFC operation include electrode type and area, use of catalysts, substrate concentration, and types of micro

1. icrobial Fuel Cell
The future of Bio-energy…M Vishal .V. Doshi
Ms in Molecular Biology (Contd.),
Skövde University,
Skövde-54162,
Sweden.

2. What is Microbial Fuel Cells (MFC) ?
A microbial fuel cell (MFC) converts chemical energy, available in a
bio-convertible substrate, directly into electricity. To achieve this,
bacteria are used as a catalyst to convert substrate into electrons.
A typical microbial fuel cell consists of anode and cathode
compartments separated by a cation (positively charged ion)
specific membrane. In the anode compartment, fuel is oxidized
by microorganisms, generating electrons and protons.
In general, there are two types of microbial fuel cells: mediator and
mediator-less microbial fuel cells.

3. Why Microbial Fuel Cells (MFC) ?
• Unlimited supply of fuel
• No reliance on foreign oil
• Little or no pollutants
• Much higher energy conversion %
• No moving parts
• No noise

4.  Anode Chamber
– Stores fuel
-->
 Cathode Chamber
– Exposed to air
<--
 Membrane - Allows for H+ passage^
 Often Platinum Catalyst
V V

5. Examples of microbial-based fuel cells
Microbe Substrate Mediator Anode Voltage
E.coli Glucose Methylene
Blue
Pt- C-cloth 625mV
Bacillus
subtilis
Glucose Thionine Vitreous
Carbon
640mV
E.coli Acetate Neutral red Graphite
felt
250mV
Pseudomonas
methanica
Methane 1-Naphthol-2-
Sulfonate indo-
2,6
dichlorophenol
Pt-black 550mV
Proteus
vulgaris
Sucrose Thionine Carbon rod 350mV

6. Molecular Biology
A General layout of a MFC in which in the anodic
compartment the bacteria can bring about
oxidative conversions while in the cathodic
compartment chemical and microbial reductive
processes can occur.
(After Rabaey & Verstraete,2005)
Mediator Shuttling Electrons
Mediator-less

7. Molecular Biology
Mediator-less
ETC in Prokaryotes

8. Molecular Biology
Summary of components
proposed to be involved
in the electron transport
from cells to the anode in
MFCs using metal
reducing microorganisms
(Geobacter species).
(Figure drawn with
modifications after Lovley
et al., 2004.)

9. Significant Factors Affecting
MFC Operation
 Type of electrodes
 Surface area of electrodes
 Use of catalysts
 Conc. of hydrocarbon in anode chamber
 Agitation of hydrocarbon molecules
 Rate of replacement of hydrocarbons
 Types of microbes/enzymes
 Conc. of microbes/enzymes

10. Pollution…An Example

11. Pollution…Bacteria
+

12. Pollution…Electricity
+ =
Bioremediation, which uses microbes
like Geobacter metallireducens and
S. oneidensis to facilitate removal of
contaminants, allows on-site
treatment.
+
Electricity (side
product)

13. Conclusion..!?

14. Thank you for
patient listening