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MICROBIAL FUEL CELLS AS AN ALTERNATIVE ENERGY SOURCE: A COMPREHENSIVE REVIEW
C. LAVANYA*
RAJESH DHANKAR** SUNIL CHHIKARA***
*University Institute of Engineering & Technology, Maharshi Dayanand University, Rohtak, Haryana, India
**Dept. of Environmental sciences, Maharshi Dayanand University, Rohtak, Haryana, India
***University Institute of Engineering & Technology, Maharshi Dayanand University, Rohtak, Haryana, India
ABSTRACT
The microbial fuel cell (MFC) is a very promising technology that can use microbial
metabolism for various applications from wide range of organic substrates. MFC systems
have been primarily explored for their use in bioremediation and bioenergy applications;
however, these systems also offer a unique strategy for the cultivation of synergistic
microbial communities. Sustainable energy production from organic wastes is gaining
research interest from last few years. The living cells in the anode chamber utilize substrate
for the growth maintenance, as a result of electrons are supplied. The goal of the present
review is microbial fuel designing and its characteristics, types, advantage and limitations.
KEYWORDS: Microbial Fuel Cell, Substrates, Sustainable Energy, Bioremediation,
Bioenergy, Electrons.
INTRODUCTION
Energy has become an important part of everybody human life which is
compromising the environmental protection (Singh et al., 2012). There is no doubt that the
world’s increasing population is rapidly depleting planet’s finite energy resources. The
demand of energy is rapidly increasing, so saving programs is being implemented. Use of
fossil fuels, have raised the demand for new and clean sources of energy. Low reserves of
fossil fuels and the environmental impact of their use to produce energy are leading to a
search for novel renewable energy technologies. The microbial fuel cell (MFC) is a new form
of renewable energy technology that can generate electricity from waste. Microbial fuel cell
(MFC) is a device that converts chemical energy into electrical energy by using
microorganisms. Energy demand has been projected to grow more than 50% by 2025
(Ragauskas et al., 2006). Microbial Fuel Cells (MFCs) are a type of biofuel cell which has
recently attracted considerable interest (Deval, 2013). This review states the MFC with
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emphasizes on the recent advances in MFC reactor designs, MFC performances and
optimization of important operating parameters.
As a way of increasing the performance of MFCs, there has been considerable work on MFC
configurations which are as follows:-
1. Their physical and chemical operating conditions.
2. The choice of microorganisms.
3. Optimization of the microbial metabolism to increase electron donation to the electrodes.
As a result, currently achievable MFC power production has increased by several orders of
magnitude in less than a decade (Logan, B.E, 2008).
History of Microbial Fuels
In an attempt to produce electricity, the idea of using microbial cells was first conceived in
the early twentieth century. More than 70 years after William Grove in 1839 built the first
fuel cell, Potter 2013). M. Potter a professor of botany at the University of Durham described
microbial conversion to create electrical current (Devala et al., 2013) from E.coli in 1911
(Potter, 1911). In 1911, Potter and co-workers observed for the first time that bacterium can
produce electrical current. Research in this new field of microbial electricity remained
dormant for up to 55 years until the 1990s. In 1931, however, Barnet Cohen drew more
attention to the area when he created a number of microbial half fuel cells that, when
connected in series, were capable of producing over 35 volts, though only with a current of 2
milliamps (Cohen, B. (1931). Electricity generation and waste water treatment using
Microbial Fuel Cells are among such technologies.
Increasing interest and a dramatic raise in the number of publications in the field of MFC
research due to the discovery that microbial metabolism could provide energy in the form of
an electrical current. These systems are very adaptable and hold much promise to provide
energy in a sustainable fashion (Singh et al., 2012). Microbial fuel cells exploit the energy
metabolism of microbes that electrically interact with the conductive surfaces in the system
called electrodes. In May of 2007, the University of Queensland, Australia, completed its
prototype MFC, as a cooperative effort with Fosters Brewing Company. The prototype, a 10
liter design, converts the brewery waste water into carbon dioxide, clean water, and
electricity. With the prototype proven successful, plans are in effect to produce a 660 gallon
version for the brewery, which is estimated to produce 2 kilowatts of power. Worst drought
in Australia over 100 years so, the production of clean water is of utmost importance to
Australia, while it’s a negligible amount of power.
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Set up of Microbial fuel cell
The microbial fuel cell consists of an anode, which accepts electrons from the microbial
culture, and a cathode, which transfers electrons to an electron acceptor. The anode
compartment is typically maintained under anaerobic conditions, whereas the cathode can be
suspended in aerobic solutions or exposed to air. Electrons flow from the anode to the
cathode through an external electrical connection that typically includes a resistor, a battery
to be charged or some other electrical device. The anode and cathode are often separated by a
semipermeable membrane that restricts oxygen diffusion from the cathode chamber to the
anode chamber, while allowing protons that are released from organic matter metabolism, or
oxidation of reduced metabolic products, to move from the anode to the cathode. At the
cathode, electrons, protons and oxygen combine to form water and harvesting electricity with
microorganisms (Derek R. Lovley, 2006).
This is shown by the microbial decomposition of sugars in aerobic conditions produces
carbon dioxide and water (Scott and Murano, 2007).
C6H12O6 + 6H2O + 6O2 6CO2 + 12H2O (1)
However, in anaerobic conditions carbon dioxide, protons and electrons are produced since
oxygen is not available to take up the electrons.
C6H12O6 + 6H2O 6CO2 + 24H+ + 24e- (2)
Microbial fuel cells (MFCs) as a promising and challenging technology have emerged in
recent years. Thus, there is great interest for finding the most cost effective clean and
sustainable energy resources and energy conversion technology with very low or zero
emission as well as a cost effective technology (B. Min,et al., 2005). Because of its low or
zero emission of green house gases recently, the fuel cell, a highly efficient energy converting
device has attracted special attention of energy policy makers and researchers alike, (H. Liu
et al., 2006). In a MFC, microorganisms interact with electrodes using electrons, which are
either removed or supplied through an electrical circuit (Rabaey et al., 2007). The efficiency
of microbial fuel cells is, however, constrained by diffusion of oxygen into the anode
chamber due to the severe potential drops associated with microbial consumption of oxygen
(Davis et al., 2007).
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Fig. 1. MFC setup (anode chamber containing two electrodes on the left; cathode on right)
(Logan et. al, 2008)
Electron transfer mechanism
Fig. 2. (A) Simplified view of a two-chamber MFC with possible modes of electron transfer
is shown. (1) Direct electron transfer (via outer membrane cytochromes); (2) electron transfer
through mediators; and (3) electron transfer through nanowires. (B) Single-chamber MFC
with open air cathode. Electrons transfer via the external circuit to the cathode chamber
where electrons, protons and electron acceptor (mainly oxygen) combine to produce water
(Li et al., 2009).
Types of Microbial Fuel Cells
Basically, there are two types of MFC, Mediator microbial fuel cell and Mediator-free
microbial fuel cell. In case of Mediator Microbial fuel cell, most of the bacterial species used
in MFC are inactive for transport of electron; hence for intervention, synthetic and natural
compounds called redox mediators are required. Dye mediators such as neutral red,
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methylene blue, thionine, humic acid are used as a mediator (Ghangrekar et al., 2006). A
major breakthrough in pioneering MFC research by Kim et al., in 1999 discovered that
electron transfer from bacteria to the electrode does not always need mediator molecules.
Most of the mediators available are expensive and toxic.
Whereas second type of mediator-free microbial fuel cells do not require a mediator but uses
electrochemically active bacteria to transfer electrons to the electrode (electrons are carried
directly from the bacterial respiratory enzyme to the electrode). Mediator less MFCs can be
considered to have more commercial potential then MFCs that require mediators because the
typical mediators are expensive and toxic to the microorganisms (Bond et al., 2003).
Shewanella putrefaciens, Geobacter sulfurreducens, Geobacter metallireducens and
Rhodoferax ferrireducens are the organism which have been shown to generate electricity in
a mediatorless MFC However, one major disadvantage of the two chamber system is that the
cathode chamber needs to be filled with a solution and aerated to provide oxygen to the
cathode (Zielke, 2006).
Design and operations of MFCs
The design of MFC plays a major role in the performance of the system in terms of power
output, coulombic efficiency and stability. Two such general designs are available viz. single
chamber MFC and multiple chambered MFC. Based upon assembly of anode and cathode
chambers, a simple MFC prototype can either be a double chambered or single chambered.
Besides these two common designs, several adaptations have been made in prototype of MFC
design and structure (Pant et al., 2010). The same operating principles share by many types
of reactors. Different configurations of MFCs are being developed using a variety of
materials. They are operated under different conditions to increase the performance, power
output and reduce the overall cost.
Single chamber MFC: This design has only one compartment that contains both the anode
and the cathode. The anode is either placed away or close to the cathode separated by proton
exchange membrane. Liang et al., (2007) reported that if the anode is closer to the cathode, it
reduces internal ohmic resistance by avoiding the use of catholyte as a result of combining
two chambers and thus increases the power density. Compared to the two chambers of MFC,
it offers simple, cost effective design and produces power in a more efficient way (Du et al.,
2007). However, in the membrane-less configuration, microbial contamination and back
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diffusion of oxygen from cathode to anode without proton exchange membrane are the major
drawbacks (Kim, 2008). Carbon electrode (Graphite) were used at both the ends of cathode
and anode and tightly fixed with the containers containing medium, culture and buffer
(Ayachi et al., 2013).
Two chamber MFC: This is the most widely used design consisting of two chambers with
the anode and cathode compartments separated by an ion exchange membrane. This design is
generally used in basic research and suggests that the power output from these systems are
generally low due to their complex design, high internal resistance and electrode based losses
(Du et al., 2007; Logan and Regan, 2006; Nwogu, 2007).
Up-flow MFC: The cylinder shaped MFC consists of the anode (bottom) and the cathode
(top) partitioned by glass wool and glass beads layers. The feed is supplied from the bottom
of the anode passes upward of the cathode and exits at the top. The diffusion barrier among
the electrodes provides a gradient for proper operation of the MFCs (Du et al., 2007; Kim
2008; Schwartz, 2007). This design has no physical separation and so there are no proton
transfer associated problems and is attractive for wastewater treatment (Kim 2008).
Stacked MFC: In this design, several single cell MFCs are connected together in series or in
parallel to achieve high current output (Du et al., 2007). Due to higher electrochemical
reaction rate, a parallel connection can generate more energy than a series connection when
operated at the same volumetric flow but is prone to higher short circuiting compared to a
series connection (Aelterman et al., 2006; Schwartz, 2007).
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Fig 3: Microbial fuel cell configurations (Zhuwei et al., 2007; Sengodon et al., 2012).
Microbes used in microbial fuel cells
Many microorganisms possess the ability to transfer the electrons derived from the
metabolism of organic matters to the anode. MFCs operated using mixed cultures currently
achieve substantially greater power densities than those with pure cultures. Recently the
increased interest in microbial fuel cell (MFC) technology was highlighted by the naming of
Geobacter sulfurreducens KN400, a bacterial strain capable of high current production, as
one of the top 50 most important inventions for 2009 by time magazine (Samatha et al.,
2012). These microorganisms have high Coulombic efficiency and can form biofilms on the
anode surface that act as electron acceptors and transfer electrons directly to the anode
resulting in the production of more energy (Khare, 2012). Lists of microbes are shown in
table 1 with their aim and waste source.
Table 1 Microbes with their aim and source.
Microorganism Aim Waste source/Substrate
References
Shewanella putrefaciens Bioelectricity production and waste water treatment (Gil et al., 2003).
Starch Bond and Lovley 2003, Kim et al., 1999a, Kim et al., 1999b, Kim et al., 2002, Schroder et al., 2003.
Geobacter sulphur reducens
Bioelectricity production and waste water treatment
Acetate Bond and Lovley 2003.
Geobacter metallireducens
Mediator-less MFC Acetate Min et al., (2005).
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Operational factors of Microbial fuel cells
The operational factor that affected the performance of MFC includes the pH, Dissolved
oxygen concentration, material type and surface area of electrode, temperature, presence of
catalyst and electrolyte strength. Power losses occur in MFC due to over potential and losses
Rhodoferax ferrireducens
Mediator-less MFC Glucose, xylose, sucrose, maltose
Chaudhuri and Lovley 2003.
Clostridium acetobutylicum and Clostridium thermohydrosulfuricum
Bioelectricity Production Cellulosic waste Abhilasha S Mathuriya et al., 2009.
Geobacteraceae Open lake`electricity and bioremediation of organic contaminants in Subsurface environments
Organic matter in marine sediments
Daniel R.Bond et al., 2002
Synechococcus sp Bioelectricity production Light as a fuel Tsujimura et al., 2001
Yogurt bacteria and methylene blue as mediator
Bioelectricity production Waste carbohydrate (manure sludge)
Keith et al., 2007
Pseudomonas putida, Saccharomyces cerevisiae, Lactobacillus bulgaricus, Escherichia coli and Aspergillus niger
Low Voltage Power Generation
Glucose M. Rahimnejad et al., 2009
Anaerobic mixed consortia
Bioelectricity Production Waste water S. Venkata Mohan et al., 2007, O. Lefebvre et al., 2008
Shewanella oneidensis Anthraquinone 2,6 disulfonate as mediator
Lactate
Ringeisen et al., (2006)
Aeromonas hydrophila
Mediator-less MFC
Acetate
Pham et al., (2003)
Mixed population Bioelectricity Production and waste water treatment
Sugar Habermann & Pommer,1991
Mixed population Bioelectricity Production Decay Organics Reimers et al., 2001
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which can be minimized by MFC reactor configuration, electrode type, surface area and
spacing, use of protons-selective Proton exchange membrane. Larger surface area electrode
has shown result of threefold higher current and closer electrode spacing between the anode
and cathode reduces the internal resistance of the MFC thereby improving, proton transport.
The level of dissolved oxygen affects the performance of MFCs as because the presence of
oxygen greatly improves on the proton sink as electron acceptor in the cathode but also plays
an inhibitory role on anaerobic anodic bacteria (Oji et al., 2012).
Substrate
A substrate is the substance contained in anode chamber that is to be oxidised. In a microbial
fuel cell the substrate used can be any form of organic matter. Cells have been successfully
operated on chocolate (Markusic, 2010), wine (Danigelis, 2009), wastewater, glucose (Logan,
2008), acetate (Liu et al., 2005) and more. Most frequently glucose, wastewater and acetate
are used in experiments with the highest results being obtained with acetate (Sun et al., 2008).
Electrode
Microbial fuel cells exploit the energy metabolism of microbes that electrically interact with
the conductive surfaces in the system called electrode (Bretschger, 2009). Studies have
shown that the MFCs using expensive solid graphite electrodes, but less expensive graphite
felt and carbon cloth, can also be used (Bond and Lovely 2003, Tender et al., 2002,
Chundhuri and Lovely 2003, Lui et al., 2004).
Anode
The most versatile electrode material is carbon, available as compact graphite plates, rods or
granules, as fibrous material (felt, cloth, paper, fibers, and foam) and as glassy carbon.
Carbon fiber, paper, foam and cloth (Toray) have been extensively used as electrodes (Sing et
al., 2010). In addition, bacteria attachment, electron transfer and substrate oxidation can be
directly affected by anode. Carbonaceous materials are the most widely used materials for
MFC anodes because of their good biocompatibility, good chemical stability, high
conductivity, and relatively low cost. In terms of configuration, carbon-based electrodes can
be divided into a plane structure, a packed structure, and a brush structure (Wei et al., 2011)
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Cathode
Most MFC’s use platinum as the catalyst is extremely expensive. Chemicals such as
ferricyanide and potassium permanganate have been used successfully with results
comparable to those achieved with platinum (He & Angenent, 2006). Using ferricyanide as
the electron acceptor in the cathode chamber increases the power density due to the
availability of a good electron acceptor at high concentrations. Bacteria then assist the
reduction of oxygen without the need for any additional chemicals or substances. Most
commonly used materials include carbon, graphite and steel. Most of the materials mentioned
above used as the anode have also been used as the base materials of air–cathodes, aqueous
air–cathodes, and bio-cathodes. The main difference in these materials used for the cathode is
that a catalyst (i.e., Pt for oxygen reduction) is normally used but is not always necessary
(i.e., ferricyanide) (Logan, 2007). Steel has been found to be less effective for use in
microbial fuel cells as it is not a porous material and bacteria appear to be unable to attach
themselves. Carbon and graphite are both widely available materials which has many forms.
Carbon is available as paper, cloth and foam while graphite comes in the form of rods,
granules and brushes. Platinum is a critical catalyst at the cathode and no alternative metal
has been proven to catalyze the combination of oxygen, the hydrogen proton, and the electron
in a more efficient manner (Oh et al., 2004).
Reactor
Reactors have been cube shaped, cylindrical, horse shoe shaped, two chamber and single
chamber and H-type configured and made of glass and various types of plastic, even buckets.
Sizes also vary widely with some reactors having volumes of a few square centimetres and
others of up to a square metre. So far researchers have speculated that single chamber
reactors may show the most promise but this has not deterred people from using two chamber
types. In terms of construction difficulties a single chamber reactor can be the harder of the
two chambered. The total reactor capacity will be 1.1L, 600mL in the anode chamber and
500mL in the cathode chamber.
Membrane
Synthetic membranes include anion exchange membranes, cation exchange membranes and
ultra filtration membranes. Studies have shown that anion exchange membranes perform
better than cation exchange membranes due to a lower resistance (You et al., 2009). These
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types of membranes are generally very expensive, have high minimum orders or large freight
charges as they are only manufactured overseas. An alternative is membrane inclusive water
resistant clothing such as Gore-Tex. Higx. High quality clothing is specially made to contain
a membrane within the fabric to repel water. The fabric is suitable for fuel cell applications as
it successfully separates the liquids in the two chambers whilst allowing protons to flow from
the anode to the cathode chamber. The limitation to wide-spread utilization of microbial fuel
cells as an alternative energy source is that, at present, the power densities of microbial fuel
cells are too low for most envisioned applications (Derek R Lovley, 2008). Proton exchange
membranes such as Nafion are also expensive and if removed, can substantially reduce the
overall cost of the microbial fuel cells.
ADVANTAGES
MFCs have operational and functional advantages over the technologies currently used for
generating energy from organic matter.
The direct conversion of substrate energy to electricity enables high conversion
efficiency.
MFCs operate efficiently at ambient temperature.
MFC does not require gas treatment because the off-gases of MFCs are enriched in
carbon dioxide and normally have no useful energy content.
MFCs do not need energy input for aeration provided the cathode is passively aerated
(Liu et al., 2004).
MFCs have potential for widespread application in locations lacking electrical
infrastructures and can also operate with diverse fuels to satisfy our energy
requirements.
Some recent developments allow high conversion rates and high conversion efficiencies of
simple carbohydrates like glucose (Rabaey et al., 2003), and complex carbohydrate like
starch (Niessen et al., 2004) and cellulose (Niessen et al., 2005). Although MFCs generate a
lower amount of energy than hydrogen fuel cells, a combination of both electricity production
and wastewater treatment would reduce the cost of treating primary effluent wastewater
(Mathuriya et al., 2009).
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Applications
1. Education- Soil-based microbial fuel cells are popular educational tools, as they
employ a range of scientific disciplines (microbiology, geochemistry, electrical
engineering, etc.), and can be made using commonly available materials, such as soils
and items from the refrigerator. There are also kits available for classrooms,
hobbyists, and research-grade kits for scientific laboratories and corporations.
2. Biosensor - Bio-sensors could be constructed, in which bacteria are immobilized onto
an electrode and protected behind a membrane. If a toxic component diffuses through
the membrane, this can be measured by the change in potential over the sensor. Such
sensors could be extremely useful as indicators of toxicants in rivers, at the entrance
of wastewater treatment plants, to detect pollution or illegal dumping, or to perform
research on polluted sites (Meyer et al., 2002, Chang et al., 2004).
3. Desalination of marine water - Salt removal efficiencies of up to 90% have been
recorded in laboratory work, but much higher removal efficiencies are required to
produce drinking-quality water.
4. Hydrogen production - Although electricity is used instead of generated as in normal
MFCs, this method of producing hydrogen is very efficient because more than 90% of
the protons and electrons generated by the bacteria at the anode are turned into
hydrogen gas (Rabaey et al., 2005).
5. Waste water technology - The amount of power generated by MFCs in the
wastewater treatment process can potentially halve the electricity needed in a
conventional treatment process that consumes electrical power aerating activated
sludges (Ghasemi, 2013). MFC has found application in monitoring and control of
biological waste treatment unit. This is obtainable due to correlation of Coulombic
yield of MFC and strength of organic matter in wastewater which serves as biosensor
(Oji et al., 2012). MFC integrated wastewater treatment plants can recover energy and
reduce excess sludge production with little effect on the mineralization of organic
load and the rest of the process. However, for the process to be economically feasible,
it is necessary to cut cost by either eliminating the cationic membrane and reducing
cost of membrane maintenance or using a cheaper membrane, running MFC in
existing wastewater treatment plants, and avoid expensive cathode catalysts in favor
of aerobic biomass. Application of MFCs for wastewater treatment has become very
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attractive because of the double benefit of recovering energy from the wastewater as
well as reducing the BOD and excess sludge production.
Limitations
Despite the rapid progress, there are some areas in which further research needs to be
done to overcome the constraints associated with MFC are as follows:
1. Low Power: The main problem with practical application of the MFC is the low
power output, which is mainly caused by the difficult electron transfer between the
bacteria and the electrode (Ghasemi, 2013). Saldago (2009) reported that the current
generation is only 14mA, which could power only small devices. Kim et al., (2007)
reported that even using similar biocatalyst and substrate showed differences in the
power density. Abhijeet et al., (2009) reported that the power obtained from MFCs is
about 300 Wm3 which is low for commercial applications.
2. Microbe/electrode Interaction: Current production by bacteria in MFC is a complex
process that is regulated by more than few genes and requires further insight into the
process of electron transfer (Franks and Nevin, 2010). Cheng Iting et al., (2006)
reported that befouling of cathode affect MFC performance. Though the electron
transfer mechanism is understood in some bacteria, further research is needed to create
genetically engineered strains to generate more current (Lovely 2008). As the electrode
properties affect microorganism wiring and MFC performance, there is a need to
develop higher catalytic material with superior performance to avoid befouling,
corrosion and other degradation mechanisms of electrodes (Huang et al., 2011).
3. Large Scale: The main challenge in implementing MFC on a large scale is in
maintaining low costs, minimizing hazards while maximizing power generation
(Schwartz, 2007). The performance of the MFCs is influenced by current, power
density, fuel oxidation rate, loading rate and coulombic efficiency (Balat, 2009; Kim et
al., 2007). The power density is affected by high internal resistance or over potential
related ohmic, activation and mass transfer losses (Logan and Regan, 2006) whereas
the fuel oxidation rate is influenced by anode catalytic activity, fuel diffusion, proton
and electron diffusion and consumption (Balat, 2009).
4. Diffusion of Fuel/Coulombic efficiency: Min et al., (2005) described that diffusion of
oxygen into the anode chamber lowers the coulombic efficiency by more than half
(55% to 19%) and reduces the power output. It has also been suggested that coulombic
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efficiency and maximum theoretical amount of energy depend on complete oxidation
of substrate to Carbon dioxide (Franks and Nevin, 2010). Geothrix fermentans and
Geobacter has the ability to oxidize the substrate completely (94-100% coulombic
efficiency by oxidizing acetate), whereas Shewanella oneidensis has only partial
oxidation ability (56%).
5. Electron Spacing: The internal resistance can be minimized by reducing the electrode
spacing, increasing the electrode surface area, using highly selective proton membrane
and increasing catalyst activity (Oh and Logan, 2006). Liu et al., (2005) showed that
closer electrode spacing increased the power density by 68%. Chaudhuri and Lovely
(2003) described threefold increase in current with larger surface area of electrode
material. The performance is also affected by factors such as pH, temperature,
substrate, and microbial activity, resistance of circuit and electrode material.
6. pH: Yong Yuan et al., (2011) found that alkaline conditions (pH 9) shows electricity
generation by enhancing electron transfer efficiency. However, Gil et al., (2003)
reported that the highest current was obtained in the pH 7 to pH 8 ranges but not pH 9
or above.
7. Reactors: The power density decreases as the system size increases and further
improvements are needed to construct highly efficient reactors with reduced internal
resistance and electrode over-potential to maximize power in large scale systems
(Cheng and Logan, 2011).
8. Voltage reversal: When the voltage in the cells is not matched or when one cell
suffers the loss of fuel or shows higher resistance than other cells. Oh and Logan
(2007) reported that voltage reversal 5 is a problem in fuel cells due to substrate
starvation in cells that resulted in reduced power generation. High resistance remains a
barrier in MFCs (Nwogu, 2007).
Conclusions
In the present study we have present an overview of MFCs and its limitations, identify
several potential applications of the technology to advancing knowledge. As has been
discussed, MFCs are an emerging platform that contributes to a greater understanding of
complex microbial systems. The research opportunities provided by MFC technology extend
beyond the generation of electricity and represent a unique opportunity to study and control
the waste. While low current density and long time of operation is its biggest drawbacks, as
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energy production systems with great potentials. The world’s need for electricity and fuel is
ever increasing and so is the need for clean, renewable methods to produce these things. The
study also discussed the design and construction details of two MFCs and presented the
results of test carried out with the constructed cell. Reducing the expenses of building and
operating an MFC system as well as increasing cell efficiencies are ongoing issues for the
technology. Further research is also required in many areas particularly in the area of
catalysts as the cathode with the inclusion of the catalyst has been found to account for
almost fifty percent of the cost of an MFC/MEC. Future studies should focus on the
incorporation of bacteria on the cathode to replace the current techniques.
REFERENCES
1. Animesh Devala and Anil Kumar Dikshit, Construction. 2013.Working and Standardization of Microbial Fuel Cell. ICESD: January 19-20, Dubai, UAE. APCBEE Procedia 5: 59 – 63.
2. Amit Prem Khare, Rani Ayachi, 2012. Evaluation of the Effect of Cultural Conditions for Efficient Power Generation by Pseudomonas using Microbial Fuel Cell System. International Journal of Science and Research. Volume 1 Issue 3..
3. Bond, D.R.; Lovely, D.R. 2003. Electricity production by Geobacter sulfurreducens attached to electrodes. Appl. Environ. Microbial 69 : 1548-1555.
4. B. Min, S. Cheng, B. Logan, Water Research 39 (2005) 1675–1686. 5. Chang, I. S., Jang, J. K., Gil, G. C., Kim, M., Kim, H. J., Cho, B. W., Kim, B. H. 2004. Continuous
determination of biochemical oxygen demand using microbial fuel cell type biosensor. Biosens. Bioelectron. vol. 19: pp.607-613.
6. Chen GW, Choi SJ, Lee TH, Lee GY, Cha JH and Kim CW. 2008. Application of biocathode in microbial fuel cells: cell performance and microbial community. Applied Microbiology and Biotechnology 79 379-388.
7. Chaudhuri SK and Lovley DR. 2003. Electricity generation by direct oxidation of glucose in mediator less microbial fuel cells. Nature Biotechnology 21: 1229-1232.
8. Cagil Ozansoy and Ruby Heard, Microbial Conversion of Biomass: A Review of Microbial Fuel Cells. 9. Dr. Hemlata Bundela, Amit Khare , Use of Microbial Fuel Cell for the Evaluation of Power
Generation, International Journal of Engineering Technology & Management Research. 10. Derek R Lovley 2008. The Microbe Electric: Conversion Of Organic Matter To Electricity, Cobiot-
578; No Of Pages 8. 11. D. Singh, D. Pratap, Y. Baranwal, B. Kumar and R. K. Chaudhary. 2010. Microbial fuel cells: A green
technology for power generation, Annals of Biological Research, 1 (3): 128-138, ISSN 0976-1233. 12. Du Z, Li H and Gu T. 2007. A state of the art review on microbial fuel cells: A promising technology
for wastewater treatment and bio-energy. Biotechnology Advances 25: 464-482. 13. Eric A. Zielke, February 15, 2006 Application of Microbial Fuel Cell technology for a Waste Water
Treatment Alternative. 14. Feng Y, Wang X, Logan B and Lee H. 2008. Brewery wastewater treatment using air-cathode
microbial fuel cells. Applied Microbiology and Biotechnology 78 873-880 15. F. Davis and S. P. J. Higson, 2007. Biosens. Bioelectron. 22:1224. 16. H. Liu, C. Song, L. Zhang, J. Zhang, H. Wang, D.P. Wilkinson, Journal of Power Sources 155 (2006)
95–110. 17. Ishwar Chandra (2012). Amity Institute of Biotechnology, Amity University, Noida sector-125, UP,
India. Waste To Energy: Microbial Fuel Cell A Novel Approach To Generate Bio-Electricity International Journal Of Advanced Biotechnology And Bioinformatics Vol.1, Issue.1, November, 2012.
18. John V. Nwokocha, Nwaulari, J. Nwokocha , Lebe, A. Nnanna. The Microbial Fuel Cell: The Solution to the Global Energy and Environmental Crises. Journal of Biotechnology ISSN: 2319-3859 (Online).
19. Jincheng Wei, Peng Liang, Xia Huang, 2011.Recent progress in electrodes for microbial fuel cells Bioresource Technology 102: 9335–9344.
JOURNAL OF INTERNATIONAL ACADEMIC RESEARCH FOR MULTIDISCIPLINARY Impact Factor 1.393, ISSN: 2320-5083, Volume 2, Issue 4, May 2014
722 www.jiarm.com
20. Jump upJump up^ Research-Grade BES Test Kits. 21. Keego Technologies - MudWatt MFC. 22. K. Rabaey and W.Verstraete. "Microbial fuel cells: novel biotechnology for energy generation." Trends
in Biotechnology 23.6 (2005): 291-98. Print. 23. Kim, N., Choi, Y., Jung, S. and Kim, S. Development of Microbial Fuel Cells using Proteus vulgaris.
Bull. Korean Chem. Soc, 21 (1), 44-48. 2000. 24. Li, Y. et al., 2010. Microbial fuel cells using natural pyrrhotite as the cathodic heterogeneous Fenton
catalyst towards the degradation of biorefractory organics in landfill leachate. Electrochem. Commun. 12 (7), 944–947.
25. Logan, B.E., 2008. Microbial Fuel Cells. John Wiley and Sons, Inc., New Jersey. 26. Lee, J., Phung, N. T., Chang, I. S., Kim, B. H. and Sung, H. C. (2003) Use of acetate for enrichment of
electrochemically active microorganisms and their 16S rDNA analyses. FEMS Microbiol. Lett. vol. 223(2): pp.185-191.
27. Logan,b.e and regand.m2008. Electricity producing bacterial communities in microbial fuel cells, trends microbial, 512-518.
28. Logan, B.E., Cheng, S., Watson, V., Estadt, G., 2007. Graphite fiber brush anodes for increased power production in air-cathode microbial fuel cells. Environ. Sci. Technol. 41, 3341–3346.
29. Modified Microbial Fuel Cell Produces Electricity and Desalinates Water." FuelCellsWorks: Leader in the Fuel Cell Industry. Internet: http://fuelcellsworks.com/news/2009/08/09/modified-a-microbial-fuel-cell-produces-electricity-and-desalinates-water/, Aug. 9, 2009. [Mar. 19, 2010].
30. M.M. Ghangrekar and V.B. Shinde, Wastewater Treatment in Microbial Fuel Cell and Electricity Generation: A Sustainable Approach , Paper presented in the 12th international sustainable development research conference, April 6-8, 2006.
31. Meyer, R. L., Larsen, L. H. and Revsbech, N. P. (2002). Microscale biosensor for measurement of volatile fatty acids in anoxic environments. Appl. Environ. Microbiol. vol. 68: pp.1204-1210.
32. Mostafa ghasemi, Wan ramli wan daud, Sedky H.A. Hassan, Sang-eun oh, Manal ismail, Mostafa rahimnejad, Jamaliah md jahim (2013). Nano-structured carbon as electrode material in microbial fuel cells:a comprehensive review. Journal of alloys and compounds 580 (2013) 245–255.
33. Nwogu, N.g. (2007). Microbial fuel cells and parameters affecting performance when generating electricity. Basic Biotech, 73-79.
34. Oji, C.C. Opara and M.K. Oduola, Fundamentals and Field Application of Microbial Fuel cells (MFCs), Scientific Research, 2012, 1 (4):185-189.
35. Orianna Bretschger&Jason B. Osterstock& William E. Pinchak&Shun’ichi Ishii&Karen E. Nelson, 2009. Microbial Fuel Cells and Microbial Ecology: Applications in Ruminant Health and Production Research.
36. Padma Sengodon and Dirk. B. Hays, Microbial Fuel Cells, Future Fuel Technologies, National Petroleum Council (NPC) Study, Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas – 77843.
37. Pant D, Bogaert G V, Diels L & Vanbroekhoven K (2010), A review of the substrates used in microbial fuel cells (MFCs) for sustainable energy production, Biores Technol, 101 (2010) 1533-1543.
38. Pant, D., Van Bogaert, G., Diels, L., Vanbroekhoven, K., 2010. A review of the substrates used in microbial fuel cells (MFCs) for sustainable energy production. Bioresour. Technol. 101 (6), 1533–1543.
39. Rabaey, K., Boon, N., Siciliano, S. D., Verhaege, M. and Verstraete, W. (2004a) Biofuel cells select for microbial consortia that self-mediate electron transfer. Appl. Environ. Microbiol. vol. 70(9): pp.5373-5382.
40. Ragauskas A.J., Williams, C.K., Davison, B.H., Britovsek G., Cairney J., Eckert C.A., et al., The path forward for biofuels and biomaterials. Science. 2006; 311: 484-489.
41. Rabaey K, Boon N, Siciliano SD, Verhaege M and Verstraete W (2004). Biofuel cells select for microbial consortia that self-mediate electron transfer. Applied Environmental Microbiology 70 5373-5382.
42. Samatha Singh and Durgesh Singh Songera (2012). A review on microbial fuel cell using organic waste as feed, Cibtech journal of biotechnology issn: 2319-3859 (online).
43. You, S.J., Zhao, Q.L., Jiang, J.Q., Zhang, J.N., Zhao, S.Q., 2006. Sustainable approach for leachate treatment: electricity generation in microbial fuel cell. J. Environ. Sci. Health Part A 41, 2721–2734.
44. Zhuwei Du , Haoran Li , Tingyue Gu, 2007. A state of the art review on microbial fuel cells: A promising technology for wastewater treatment and bioenergy.