Microbial fuel cells are devices that use bacteria to turn the energy stored in chemical bonds into electrical current that we can use without the need for combustion. Essentially, we are harnessing the power of metabolism for electricity.

1. Microbial Fuel Cell
(MFC)
Manahil
khanum

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Fuel Cell
“AFuelcell isan
electrochemicalcellthatconverts
thechemicalenergyof afuel(often
hydrogen)andanoxidizingagent
(oftenoxygen)intoelectricity
throughapairof redoxreactions.”
OR
“Device that converts chemical
energy from fuel into electricity
through chemical reaction with
oxygen or another oxidizing agent.”
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» Microbial fuel cells are devices that use
bacteria to turn the energy stored in
chemical bonds into electrical current
that we can use without the need for
combustion. Essentially, we are
harnessing the power of metabolism for
electricity.
» Microbial fuel cell is a device that
converts chemical energy to electrical
energy (in a biochemical process)
by the action of microorganisms.
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Microbial Fuel cell

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 The idea of producing electricity by using
microbes was conceived in early twentieth
century.
 Michael Cresse potter initiated the subject in
1911.
 potter managed to generate electricity from
Saccharomyces cerevisiae but the work
received little coverage
 After a lot of working experiments finally
Suzuki et al produced successful MFC design.
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INVENTIONS
(MFC)

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A MFC consists of an anode and a
cathode separated by cation specific
membrane.
Microbes at the anode oxidize the
organic fuel generating protons which
pass through the membrane to the
cathode.
 Electrons which pass through the anode
to an external circuit to generate a
current.
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General working principle

6. Types of MFC
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Types of MFC
MFCs are of different types; however, the basic designs used in the laboratories
for its applications include double-chamber MFC, single-chamber MFC,
upflow MFC and stacked MFC. Moreover, some other designs have also been
used for the studies.The trick of course is collecting the electrons released
by bacteria as they respire.This leads to two types of
MFCs.
1. Mediator
2. Mediator less
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Mediator MFCs
Prior to 1999 most MFCs required a mediator chemical to transfer electrons from the
bacterial cell to the electrodes.
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Mediator less MFCs
This type of MFCs does not require mediator. In this MFC the bacteria are
electrochemically active , the bacteria had the ability to respire directly into the
electrode under certain conditions.
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Distance between electrodes(If you
are using Single chamber MFC)
The density of oxygen near
cathode.
The surface area of anode(More
surface area will gives more
attachment of microorganism.
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Factors on which voltage
generation by MFC depends?
The current obtained in MFC is depends on several factors
along with nature of microorganism like

11. Designing of
MFC
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MATERIAL REQUIRED
Copper and silver wire
Mud
Spatula
Anode and cathode wire
Voltmeter
Neutral wire
Containers
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PROCEDURE
 Copper wires and silver wires were cut off same length for using them as cathode and anode respectively.
 Two Containers (A and B) were filled with mud. and silver wires used as anode were placed into the mud in
anaerobic environment.
 Cathodes (copper wire) were placed above the mud to provide aerobic environment. It is important to ensure
that the cathode and the anode are not touching.
 For connecting the two cells in series a neutral wire was attached with anode of cell A and the cathode of the
cell B.
 The red wire was attached with the cathode of the cell A. The black wire was attached with the anode of cell
B.
 The red lead of multimeter was attached to the red wire and the black lead of multimeter to the black wire for
measuring current.
 The MFC was set at normal room temperature, where they are not disturbed. The MFC should remain at the
same place as movement can disrupt the growth of bacteria
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Observations

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DAY CURRENT
(mA)
Voltage
(V)
1 928 0.9
2 1054 1.05
3 1114 1.1
4 1241 1.2
5 1592 1.5
6 1670 1.6
7 1935 1.9
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Limitations of MFC
Limit on surface area of anode as bacteria can clog small pores and hence
limit on current.
Still not economically competitive.
Power produced way below when compared with conventional cells.
The practical value of maximum voltage achieved is very low when compared
to the theoretical value
This can be attributed to
Activation losses.
Bacterial metabolic losses.
Concentration losses
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Treatment of waste water and waste solids
 Municipal wastewater, Sanitary waste, Organic
waste from farms or industry has multitude of
organic compounds that fuel MFCs.
 About 50-90% of organic solids like aceate,
propionate and butyrate are degraded.
 COD upto 80% can be removed and has a high
coulombic efficiency of 80%.
 Since the current generated from a microbial fuel
cell is directly proportional to the strength of
wastewater used as the fuel, an MFC can be used
to measure the strength of wastewater.
 Continuous flow and single compartment MFCs
preferred
 because of scale up concerns.
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Applications
Bioelectricity
 MFC could be installed in waste water treatment
plants. The bacteria would consume waste
material from water and produce supplementary
power for the plant.
 Chemical energy of organic compouns converted
into electrical rather than heat. Hence higher
conversion energy comparable to chemical cell is
achieved.
 They can also used as power source for
environmental sensors.

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MFC in Future
Better understanding of bacterial metabolism to improve the
efficiency of MFC.
Research is going on to develop better nanomodified anode to
enhance their electron attracting properties.
These form have a stylish and futuristic vibe.
In the future, MFC’s may be linked to municipal waste streams
or sources of agricultural and animal waste, providing a
sustainable system for waste treatment and energy
production.
Great asset for our future generation.
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21. Any Queries??
Advance Topics of Microbiology
(Group Project)
(MMG- 7th Semester)
The Women University Multan 21