Journal of Scientific & Industrial Research RECENT DEVELOPMENTS IN MICROBIAL FUEL CELLS: A REVIEW
DAS & MANGWANI : 727
Vol. 69, October 2010, pp. 727-731
Recent developments in microbial fuel cells: a review
Surajit Das* and Neelam Mangwani
Department of Life Science, National Institute of Technology, Rourkela 769 008, India
Received 26 March 2010; revised 23 July 2010; accepted 26 July 2010
This review presents microbial fuel cells (MFCs) that convert biochemical metabolic energy into electrical energy.
Microbes can be fed with waste products rich in organic matter (domestic wastewater, lignocellulosic biomass, brewery
wastewater, starch processing wastewater, landfill leachates etc.) to generate electricity. MFCs can also be used for wastewater
treatment, as biosensors and production of secondary fuels like hydrogen.
Keywords: Biosensors, ETC, MFCs, Wastewater treatment
Introduction MFCs: Setup and Working Principle for Electricity
Microbial fuel cells (MFCs) employ microbes to Generation
generate electricity from biochemical energy produced Basic Machinery
during metabolism of organic substrates. MFC consists An ideal MFC apparatus (Fig. 1) consists of two
of anode and cathode connected by an external circuit chambers (anodic and cathodic) made up of glass,
and separated by proton exchange membrane (PEM). In polycarbonate or Plexiglas, with respective electrode of
anode chamber, decomposition of organic substrates by graphite, graphite felt, carbon paper, carbon-cloth, Pt,
microbes generates electrons (e-) and protons (H+) that Pt black or reticulated vitreous carbon (RVC). These
are transferred to cathode through circuit and membrane chambers are separated by PEM (Nafion or Ultrex5).
respectively1. Organic substrates are utilized by microbes Anodic chamber is filled with organic substrates that are
as their energy sources, outcome of this process is in metabolized by microbes for growth and energy
release of high-energy electrons that are transferred to production while generating electron and proton.
electron acceptors (molecular oxygen) but in absence of Cathode is filled with a high potential electron acceptor
to complete circuit. An ideal electron acceptor should
such electron acceptor in a MFC, microorganisms shuttle
not interfere with microbes in any way and must be a
electron onto anode surface that results in generation of
sustainable compound with no toxic effect. Oxygen
electricity2. Bacteria are most preferred microbes that
serves as an ideal electron acceptor due to its non-toxic
can be used in MFCs to generate electricity while effect and preferred as oxidizing reagent as it simplifies
accomplishing biodegradation of organic matters or operation of an MFC, otherwise standard media with
wastes3,4. Biodegradable organic rich waters (municipal suitable electron acceptor such as ferricyanid can also
solid waste, industrial and agriculture wastewaters) are be used to increase power density 1,6 . Based upon
ideal candidates of sustainable energy sources for assembly of anode and cathode chambers, a simple MFC
electricity production. MFCs can also be used as prototype can either be a double chambered or single
biosensors and in secondary fuel production. chambered. Besides these two common designs, several
This paper reviews recent developments in adaptations have been made in prototype of MFC
MFC technology highlighting working principle and design and structure7.
applications of MFC technology.
Double Compartment MFC System
*Author for correspondence In general, this type of MFCs has an anodic and a
E-mail: firstname.lastname@example.org, email@example.com cathodic chamber connected by a PEM that mediates
728 J SCI IND RES VOL 69 OCTOBER 2010
Fig. 1—A simple setup of microbial fuel cell (MFC)
proton transfer from anode to cathode while blocking either by a spontaneous (direct) or by means of some
diffusion of oxygen into anode. This type of system is electron shuttling mediators9. Direct electron transfer to
generally used for waste treatment with simultaneous anode by bacteria requires some physical contact with
power generation. Scaling up of two compartment MFCs electrode for current generation. Plunge line up between
to industrial size is quite tough. Moreover periodic bacteria and anode surface involves outer membrane
aeration of cathodic chambers also limits application bound cytochromes or putative conductive pili called
spectrum of double compartment MFCs6. nanowires2. These mediator-less MFCs often utilize
anodophiles to form a biofilm on anode surface to make
Single Compartment MFC System easy use of anode as their end terminal electron acceptor
In a single compartment MFC, an anodic chamber in anaerobic respiration.
is linked to a porous air exposed cathode separated by a In mediated electron transfer machinery, microbes
gas diffusion layer or a PEM. Electrons are transferred produce / acquire indigenous soluble redox compounds
to porous cathode to complete circuit. Limited (quinones and flavin) or synthetic exogenous mediators
requirement of periodic recharging with an oxidative (dye or metalloorganics) to shuttle electron between
media and aeration makes single compartment terminal respiratory enzyme and anode surface3. These
microbial fuel cell system more versatile. Among mediators can divert electrons from respiratory chain by
different advantages, single compartment MFC includes entering outer cell membrane, becoming reduced, and
its reduced setup costs (due to absence of expensive then leaving in a reduced state to shuttle electron to
membranes and cathodic chambers) that make flexible electrode10. Numbers of electron and proton fabricated
application in wastewater treatment and power depends upon substrate utilized by microbes.
Mediator-less MFCs have more commercial potential as
mediators are expensive and are sometimes toxic to
Working Principle microorganisms. Electrode reactions in a MFC
MFC explores metabolic potential of microbes for compartments are as follows:
conversion of organic substrate into electricity by i) If acetate is used as substrate
transferring electrons from cell to circuit. In anodic microbes
chamber, oxidation of substrate in the absence of
Anodic reaction: CH3COO- + H2O → 2CO2+2H++8e-
oxygen by respiratory bacteria produce electron and
Cathodic reaction: O2 +4e- +4H+ → 2H2O
proton that are passed onto terminal e - acceptor
[O2, nitrate or Fe (III)] through electron transport chain ii) If sucrose is used as substrate
(ETC) (Fig. 2). However, in absence of e- acceptor in a microbes
MFC, some microorganisms pass electron onto anode2. Anodic reaction: C12H22O11+13H2O → 12CO2+48H++48e-
An efficient electron shuttle to anode can be achieved Cathodic reaction: O2 +4e- +4H+ → 2H2O
DAS & MANGWANI : RECENT DEVELOPMENTS IN MICROBIAL FUEL CELLS: A REVIEW 729
Fig. 2—Electron shuttling mechanism in a MFC9
(from industrial and municipal wastewaters)14, synthetic
Table 1—Commonly used bacteria in MFCs
or chemical wastewater, dye wastewater and landfill
Bacteria Mode of operation leachates are some unconventional substrates used for
Actinobacillus succinogenes Requires exogenous mediators3
Erwinia dissolven Mediator based MFC16
electricity production via MFCs7.
Proteus mirabilis Mediator based17
Pseudomonas aeruginosa With exogenous mediators18 Commonly used Microbes in Microbial Fuel Cells (MFCs)
Shewanella oneidensis With exogenous mediators19 Usually mixed culture of microbes is used for
Streptococcus lactis With mediators16 anaerobic digestion of substrate as complex mixed
Aeromonas hydrophila Mediator-less MFC20
Geobacter metallireducens Mediator-less MFC21
culture permits broad substrate utilization. But there are
G. sulfurreducens Mediator-less MFC22,23 some regular MFCs designs which explore metabolic
Rhodoferax ferrireducens Mediator-less MFC24,25 tendency of single microbial species to generate
Shewanella putrefacien Mediators-less MFC26, Exogenous electricity 9 . Organic component rich sources
mediators improve electricity production27
Klebsiella pneumoniae Mediator based28 (marine sediment, soil, wastewater, fresh water sediment
and activated sludge) are rich source of microbes that
Substrate used for Electricity Generation can be used in MFCs catalytic unit15. Bacteria used in
Substrate is a key factor for efficient production of MFCs with mediator or without mediators have been
electricity from a MFC. Substrate spectrum used for extensively studied and reviewed (Table 1). Metal
electricity generation ranges from simple to complex reducing and anodophilic microorganisms show better
mixture of organic matter present in wastewater. opportunities for mediator-less operation of a MFC.
Although substrate rich in complex organic content helps
in growth of diverse active microbes but simple substrates Other Applications
considered to be good for immediate productive output. Wastewater Treatment and Electricity Generation
Acetate and glucose are most preferred substrate for basic Due to unique metabolic assets of microbes, variety
MFC operations and electricity generation. of microorganisms are used in MFCs either single
Lignocellulosic biomass from agriculture residues as species or consortia. Some substrates (sanitary wastes,
hydrolysis products (monosaccharides) are a good source food processing wastewater, swine wastewater and corn
for electricity production in MFCs11. Another promising stovers) are exceptionally loaded with organic matter that
and most preferred unusual substrate used in MFCs itself feed wide range of microbes used in MFCs. MFCs
operations for power generation is brewery wastewater using certain microbes have a special ability to remove
as it is supplemented with growth promoting organic sulfides as required in wastewater treatment 29 .
matter and devoid of inhibitory substances12. Starch MFC substrates have huge content of growth promoters
processing water can be used to develop microbial that can enhance growth of bio-electrochemically active
consortium in MFCs 13 . Cellulose and chitin microbes during wastewater treatment. This
730 J SCI IND RES VOL 69 OCTOBER 2010
simultaneous operation not only reduces energy demand reviewed focusing on recent improvement5, practical
on treatment plant but also reduces amount of implementation 39, anode performance 40, cathodic
unfeasible sludge produce by existing anaerobic limitations41, different substrates used in MFCs7 etc.
production30. MFCs connected in series have high level MFCs have been explored as a new source of electricity
of removal efficiency to treat leachate with generation during operational waste treatment4. In
supplementary benefit of generating electricity31. addition, some of the recent modification in MFCs
technology includes its use as microbial electrolysis cell
Biosensors (MEC), in which anoxic cathode is used with increased
MFCs with replaceable anaerobic consortium could external potential at cathode37. Phototrophic MFCs42 and
be used as a biosensor for on-line monitoring of organic solar powered MFC43 also represent an exceptional
matter32. Though diverse conventional methods are used attempt in the progress of MFCs technology for
to calculate organic content in term of biological electricity production.
oxygen demand (BOD) in wastewater, most of them are
unsuitable for on-line monitoring and control of Conclusions
biological wastewater treatment processes. A linear MFC is an ideal way of generating electricity since
correlation between Coulombic yield of MFC and
it not only as a renewable source but also it can be used
strength of organic matter in wastewater makes MFC a
to treat waste. It can also be used for production of
possible BOD sensor33-35. Coulombic yield of MFC
secondary fuel as well as in bioremediation of toxic
provides an idea about BOD of liquid stream that proves
compounds. However, this technology is only in research
to be an accurate method to measure BOD value at quite
stage and more research is required before domestic
wide concentration range of organic matter in waste
MFCs can be made available for commercialization.
Secondary Fuel Production References
1 Logan B E, Hamelers B, Rozendal R, Schroder U, Keller J,
With minor modification, MFCs can be employed Freguia S, Aelterman P, Verstraete W & Rabaey K, Microbial
to produce secondary fuels like hydrogen (H2) as an fuel cells: methodology and technology, Environ Sci Technol,
alternative of electricity. Under standard experimental 40 (2006) 5181-5192.
conditions, proton and electron produced in anodic cham- 2 Wrighton K C & Coates J D, Microbial fuel cells: plug-in and
power-on microbiology, Microbes, 4 (2009) 281-287.
ber get transferred to cathode, which then combines with 3 Park D H & Zeikus J G, Electricity generation in microbial fuel
oxygen to form water. H2 generation is thermodynami- cells using neutral red as an electronophore, Appl Environ
cally not favored or it is a harsh process for a cell to Microb, 66 (2000) 1292-1297.
convert proton and electron into H2. Increase in external 4 Oh S E & Logan B E, Hydrogen and electricity production from
a food processing wastewater using fermentation and microbial
potential applied at cathode can be competent to over-
fuel cell technologies, Water Res, 39 (2005) 4673-4682.
come thermodynamic barrier in reaction and used for H2 5 Du Z, Li H & Gu T, A state of the art review on microbial fuel
generation. As a result, proton and electron produced in cells: A promising technology for wastewater treatment and
anodic reaction chamber combine at cathode to form H2. bioenergy, Biotech Advances, 25 (2007) 464-482.
MFCs can probably produce extra H2 as compared to 6 Watanabe K, Recent developments in microbial fuel cell tech-
nologies for sustainable bioenergy, J Biosci Bioeng, 106 (2008)
quantity that pull off from classical glucose 528-536.
fermentation method36. Wagner et al37 reported H2 and 7 Pant D, Bogaert G V, Diels L & Vanbroekhoven K, A review of
methane production by using microbial electrolytic cells the substrates used in microbial fuel cells (MFCs) for sustain-
that are modified MFC with increased external potential able energy production, Biores Technol, 101 (2010) 1533-1543.
8 Liu H & Logan B E, Electricity generation using an air-cathode
at cathode. Thus, MFCs provide a renewable H2 to
single chamber microbial fuel cell in the presence and absence
contribute to overall H2 demand in a H2 economy. of a proton exchange membrane, Environ Sci Tech, 38 (2004)
Advancement in MFC Technology 9 Rabaey K & Verstraete W, Microbial fuel cells: novel biotech-
Development of MFCs was triggered by USA space nology for energy generation, Trends Biotechnol, 23 (2005)
program in 1960s as a possible technology for a waste 10 Bennetto H P, Stirling J L, Tanaka K & Vega C A, Anodic reac-
disposal system for space flights that would also tion in microbial fuel cells, Biotechnol Bioeng, 25 (1983)
generate power38. MFC technology has been extensively 559-568.
DAS & MANGWANI : RECENT DEVELOPMENTS IN MICROBIAL FUEL CELLS: A REVIEW 731
11 Catal T, Li K, Bermek H & Liu H, Electricity production from Shewanella putrefaciens, Appl Microbiol Biotechnol,
twelve monosaccharides using microbial fuel cells, J Power 59 (2002) 58-61.
Sources, 175 (2008) 196-200. 28 Rhoads A, Beyenal H & Lewandowshi Z, Microbial fuel cell
12 Feng Y, Wang X, Logan B E & Lee H, Brewery wastewater using anaerobic respiration as an anodic reaction and
treatment using air-cathode microbial fuel cells, Appl Microbiol biomineralized manganese as a cathodic reactant, Environ Sci
Biotechnol, 78 (2008) 873-880. Technol, 39 (2005) 4666-4671.
13 Kim B H, Park H S, Kim H J, Kim G T, Chang I S, Lee J & 29 Rabaey K, Van De Sompel K, Maignien L, Boon N, Aelterman
Phung N T, Enrichment of microbial community generating elec- P, Clauwaert P, De Schamphelaire L, Pham H T, Vermeulen J,
tricity using a fuel cell-type electrochemical cell, Appl Microbiol Verhaege M, Lens P & Verstraete W, Microbial fuel cells for
Biotechnol, 63 (2004) 672-681. sulfide removal, Environ Sci Technol, 40 (2006) 5218-5224.
14 Rezaei F, Richard T L & Logan B E, Analysis of chitin particle 30 Liu H, Ramnarayanan R & Logan B E, Production of electricity
size on maximum power generation, power longevity, and Cou- during wastewater treatment using a single chamber microbial
lombic eficiency in solid-substrate microbial fuel cells, J Power fuel cell, Environ Sci Technol, 38 (2004) 2281-2285.
Sources, 192 (2009) 304-309. 31 Gálvez A, Greenman J & Ieropoulos I, Landfill leachate treat-
15 Niessen J, Harnisch F, Rosenbaum M, Schroder U & Scholz F, ment with microbial fuel cells; scale-up through plurality, Biores
Heat treated soil as convenient and versatile source of bacterial Technol, 100 (2009) 5085-5091.
communities for microbial electricity generation, Electrochem 32 Kumlaghan A, Liu J, Thavarungkul P, Kanatharana P &
Commun, 8 (2006) 869-873. Mattiasson B, Microbial fuel cell-based biosensor for fast analy-
16 Vega C A & Fernandez I, Mediating effect of ferric chelate com- sis of biodegradable organic matter, Biosens Bioelectron, 22
pounds in microbial fuel cells with Lactobacillus plantarum, (2007) 2939-2944.
Streptococcus lactis and Erwinia dissolvens, J Bioelectrochem 33 Kim H J, Hyun M S, Chang I S & Kim B H, A microbial fuel
Bioenerg, 17 (1987) 217-222. cell type lactate biosensor using a metal-reducing bacterium,
17 Choi Y, Jung E, Kim S & Jung S, Membrane fluidity sensoring Shewanella putrefaciens, J Microbiol Biotechnol, 9 (1999)
microbial fuel cell, Bioelectrochemistry, 59 (2003) 121-127. 365-367.
18 Rabaey K, Boon N, Siciliano S D, Verhaege M & Verstraete W, 34 Chang I S, Jang J K, Gil G C, Kim M, Kim H J, Cho B W &
Biofuel cells select for microbial consortia that self-mediate elec- Kim B H, Continuous determination of biochemical oxygen
tron transfer, Appl Environ Microbiol, 70 (2004) 5373-5382. demand using microbial fuel cell type biosensor, Biosens
19 Ringeisen B R, Henderson E, Wu P K, Pietron J, Ray R, Little Bioelectron, 19 (2004) 607-613.
B, Biffinger J C & Jones-Meehan J M, High power density from 35 Chang I S, Moon H, Jang J K & Kim B H, Improvement of a
a miniature microbial fuel cell using Shewanella oneidensis microbial fuel cell performance as a BOD sensor using respira-
DSP10, Environ Sci Technol, 40 (2006) 2629-2634. tory inhibitors, Biosens Bioelectron, 20 (2005) 1856-1859.
20 Pham C A, Jung S J, Phung NT, Lee J, Chang I S, Kim B H, 36 Liu H, Grot S & Logan B E, Electrochemically assisted micro-
Hana Y & Chun J, A novel electrochemically active and Fe(III)- bial production of hydrogen from acetate, Environ Sci Tchnol,
reducing bacterium phylogenetically related to Aeromonas 39 (2005) 4317-4320.
hydrophila, isolated from a microbial fuel cell, FEMS Microbiol 37 Wagner R C, Regan J M, Sang-Eun O, Yi Z & Logan B E,
Lett, 223 (2003) 129-134. Hydrogen and methane production from swine wastewater us-
21 Min B, Cheng S & Logan B E, Electricity generation using ing microbial electrolysis cells, Water Res, 43 (2009) 1480-1488.
membrane and salt bridge microbial fuel cells, Water Res, 39 38 Bullen R A, Arnot T C, Lakemanc J B & Walsh F C, Biofuel
(2005) 1675-1686. cells and their development, Biosens Bioelectron, 21 (2006)
22 Bond D R & Lovley D R, Electricity production by Geobacter 2015-2045.
sulfurreducens attached to electrodes, Appl Environ Microbiol, 39 Rozendal R A, Hamelers H V M, Rabaey K, Keller J & Buisman
69 (2003) 1548-1555. C J N, Towards practical implementation of bioelectrochemical
wastewater treatment, Trends Biotechnol, 26 (2008) 450-459.
23 Bond D R, Holmes D E, Tender L M & Lovley D R, Electrode-
40 Pham T H, Aelterman P & Verstraete W, Bioanode performance
reducing microorganisms that harvest energy from marine sedi-
in bioelectrochemical systems: recent improvements and
ments, Science, 295 (2002) 483-485.
prospects, Trends Biotechnol, 27 (2009) 168-178.
24 Chaudhuri S K & Lovley D R, Electricity generation by direct
41 Rismani-Yazdi H, Carver S M, Christy A D & Tuovinen A H,
oxidation of glucose in mediatorless microbial fuel cells, Nat
Cathodic limitations in microbial fuel cells: an overview, J Power
Biotechnol, 21 (2003) 1229-1232.
Sources, 180 (2008) 683-694.
25 Liu Z D, Lian J, Du Z W & Li H R, Construction of sugar-based 42 He Z, Kan J, Mansfeld F, Angenent L T & Nealson K H,
microbial fuel cells by dissimilatory metal reduction bacteria, Self-sustained phototrophic microbial fuel cells based on the
Chin J Biotech, 21 (2006) 131-137. synergistic cooperation between photosynthetic microorganisms
26 Kim B H, Kim H J, Hyun M S & Park D H, Direct electrode and heterotrophic bacteria, Environ Sci Technol, 43 (2009)
reaction of Fe (III)-reducing bacterium Shewanella putrifaciens, 1648-1654.
J Microbiol Biotechnol, 9 (1999) 127-131. 43 Cho Y K, Donohue T J, Tejedor I, Anderson M A, McMahon K
27 Park D H & Zeikus J G, Impact of electrode composition on D & Noguera D R, Development of a solar-powered microbial
electricity generation in a single-compartment fuel cell suing fuel cell, J Appl Microbiol, 104 (2008) 640-650.