International Journal of Mechanical Engineering and Technology (IJMET) 
                Volume 9, Issue 9, September 2018, pp. 137–148, Article ID: IJMET_09_09_017 
                Available online at http://iaeme.com/Home/issue/IJMET?Volume=9&Issue=9 
                ISSN Print: 0976-6340 and ISSN Online: 0976-6359 
                 
                © IAEME Publication             Scopus Indexed 
                 
                   FACTORS AFFECTING THE PERFORMANCE 
                                  OF MICROBIAL FUEL CELLS 
                                        Shanmuganathan. P* and Rajasulochana. P 
                      Corresponding Author*, Bharath University, Agaram main road, Selaiyur, Chennai 
                                                  Ramachandra Murthy. A 
                        CSIR-Structural Engineering Research Centre, CSIR Road, Taramani, Chennai 
                    ABSTRACT 
                        A  microbial  fuel  cell  (MFC)  is  a  bioreactor  presents  an  advanced  eco-friendly 
                    technology   that   converts   chemical   energy   in   the   chemical   bonds   in   organic 
                    compounds to electrical energy through catalytic reactions of microorganisms under 
                    anaerobic conditions. It has been known for many years that it is possible to generate 
                    electricity  directly by  using  bacteria  to  break down  organic  substrates.  The  recent 
                    energy crisis  has  invigorated  interests  in  MFCs  among educational  researchers as 
                    some  way  to  generate  electrical  power  or  hydrogen  from  biomass  without  a  net 
                    carbon emission into the ecosystem. MFCs may be utilized in waste product treatment 
                    facilities  to  break  down  organic  matters.  MFCs  can  also  be  used  in  wastewater 
                    treatment  facilities  to  organic  matters.  It  was  also  studied  for  applications  as 
                    biosensors for biological oxygen demand monitoring. Power output and Coulombic 
                    efficiency are found to be significantly affected by the types of microbe in the anodic 
                    chamber of an MFC, configuration of the MFC and operating conditions. Presently, 
                    real-world applications of MFCs are limited because of their low power density level 
                                                  2
                    of  several  thousand  mW/m .  This  paper  presents  a  review  on  factors  affecting 
                    performance of microbial fuel cells. 
                    Keywords: MFC, Electrode materials, Bio cathodes 
                    Cite this Article: Shanmuganathan. P, Ramachandra Murthy. A and Rajasulochana. 
                    P, Factors Affecting the Performance of Microbial Fuel Cells, International Journal of 
                    Mechanical Engineering and Technology, 9(9), 2018, pp. 137–148. 
                    http://iaeme.com/Home/issue/IJMET?Volume=9&Issue=9 
                1. INTRODUCTION 
                Microbial fuel cell (MFC) is a novel technology which will be used for electricity generation 
                during oxidization of the organic substances presented in the substrate. To obtain a desirable 
                performance,  it  is  essential  to  understand  the  influential  factors  on  the  MFC.  Among  the 
                numerous factors affecting the MFC performance, (i) substrate, (ii) microorganisms and their 
                metabolism, (iii) electron transfer mechanism in an anodic chamber, (iv) electrodes material 
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                                      Factors Affecting the Performance of Microbial Fuel Cells 
                and  the  shape  of  electrodes,  (v)  type  of  membrane,  (vi)  operating  conditions  such  as 
                temperature, pH  and  salinity, electron  acceptor  in  a cathodic  chamber  and  (vii)  geometric 
                design of the MFC are considered as the most important factors. Among different substrates, 
                wastewater is a sustainable rich medium which can be treated by MFCs. There are various 
                types of exoelectrogenic bacteria presented in wastewaters which can oxidize organic matter 
                and transfer electrons to the anode without using mediators.  Like other microbial systems, 
                optimum  pH  and  temperature  enhance  the  bacterial  growth  which  can  improve  the  MFC 
                performance. Despite the negative effect of salt on microbial growth, higher salinity and ionic 
                strength can increase the conductivity of substrate and therefore enhance MFC performance. 
                Scaling up MFC is a controversial issue which needs a comprehensive understanding of these 
                factors. By using new inexpensive materials for electrodes and membrane for manufacturing 
                MFCs,  a  more  cost-effective  design  for  scalable  wastewater  treatment  and  high  power 
                generation can be achieved. Furthermore, MFC is a suitable candidate for bioremediation of 
                contaminated groundwater. 
                   Electrode design is the greatest challenge in making MFC a cost effective and scalable 
                technology.  Recently,  interest  in  the  electrode  material  and  its  configuration  has  steadily 
                increased  in  studies  for  MFC.  Over  the  past  decade,  a  variety  of  electrodes  have  been 
                extensively explored for MFC. These electrodes can be classified into two main groups, bio-
                electrodes (including anode and bio cathode) and chemical-electrodes (more specifically, air–
                cathode and aqueous air–cathode), according to whether or not bacteria is used as a catalyst. 
                A typical MFC consists of two chambers that are separated by a proton exchange membrane 
                (PEM) in which the anodic chamber is anaerobic and the cathodic chamber is aerobic [Du et 
                al., 2007].  As a substrate, the wastewater can be treated in the anodic chamber and besides 
                that the electricity will be generated [Oh et al., 2010; Du et al., 2007; Mohan et al., 2008]. In 
                some cases, bio cathodes were used in order to treat wastewater aerobically [Xia et al., 2013]. 
                By removing oxygen from the cathodic chamber and applying a small additional voltage to 
                the circuit,  hydrogen gas  is  evolved from  the cathode.  This  kind  of  biological fuel cell  is 
                called Bio-Electrochemically Assisted Microbial Reactor [Liu et al., 2005; Logan and Regan, 
                2006]. Very recently, a new type of bio electrochemical systems called microbial desalination 
                cell (MDC) was developed by keeping two membranes between the anode and the cathode in 
                MFC [Cao et al., 2009; Luo et al., 2012; Jacobson et al., 2011]. Desalination efficiency using 
                MDCs  is  limited  by  the  voltage  produced  by  the  bacteria.  In  some  cases,  microbial 
                electrodialysis  cell  was  developed  to  concurrently  desalinate  saline  waters  and  produce 
                hydrogen gas [Lou et al., 2011]. Using MDCs, wastewater treatment, electricity production 
                and water desalination is possible simultaneously [Qu et al., 2012; Kim and Logan, 2012]. 
                   This  paper  reviews  the  factors  affecting  the  performance  of  MFCs  towards  power 
                generation.  
                2. FACTORS AFFECTING THE PERFORMANCE OF MFCS 
                There are several factors that affect the performance of MFCs and its energy production in 
                wastewater treatment. In order to have a highly efficient MFC, recognizing and considering 
                these factors are essential. Microorganisms in the anodic chamber are important due to their 
                metabolism and the mediators which are used by them for transferring electron to the anode. 
                There are various substrates which can be used as the source of electron donors in the MFC 
                and  oxidized  by  microorganisms.  Operating  conditions  such  as  pH,  temperature,  ionic 
                strength of the mediums, material and construction of the anode, cathode and membrane could 
                have  a  considerable  impact  on  electricity  generation.  Figure  1  shows  a  summary of  these 
                factors. 
                    http://iaeme.com/Home/journal/IJMET        138                        editor@iaeme.com 
                                  Shanmuganathan. P, Ramachandra Murthy. A and Rajasulochana. P 
                                                                                                                       
                                       Figure 1 Factors affecting the performance of MFCs 
                2.1. Electron transfer mechanism 
                Electrons  that  are  produced  in  the  anodic  chamber  should  be  transferred  to  the  anode  by 
                shuttles or electron mediators. Some microorganisms, such as Saccharomyces species and E. 
                coli used in some MFCs, have an outer layer of non-conductive lipid membrane, including 
                peptidoglycans  and  lipopolysaccharides  that  slowdown  the  direct  electron  transfer  to  the 
                anode. The mediatorsare typically dyes such as methylene blue, neutralred, thionine, methyl 
                viologen or humic acid. 
                2.2. Microbial metabolism and cell potential 
                Microorganism  metabolic  pathway  and  the  consequent  potential  of  the  anode  is  the  main 
                parameter in determining the cell potential. Bacterial catabolism is the rate limiting step in 
                MFCs. Heterotrophic organisms gain their energy from oxidation of organic compounds. Due 
                to the involvement of exogenous oxidants, that is, external terminal electron acceptors, two 
                major  metabolic  pathway  staking  place  in  the  anodic  chamber  are  respiratory  chain  and 
                fermentation. Table 1shows several redox potential of the reactions which take place in MFC. 
                The MFC electrical potential depends on the potential differences between the cathode and 
                the anode. 
                2.3. Microorganisms 
                Either   microorganisms   or  enzymes  can  be   used  in   biofuel   cells,  however   applying 
                microorganism in biofuel cells allows multiple enzymes and, therefore, multiple substrates (or 
                mixed substrates) to be used. While purified enzymes can be used in specific and defined 
                reaction(s), this type of biofuel cells has been developed in biosensor technology in parallel 
                [Bullen et al., 2006]. MFC can be inoculated by pure or mixed culture of bacteria. Mixed 
                cultures are more beneficial in comparison with pure cultures due to their nutrient adaptability 
                and stress resistance [Mathuriya, 2013]. Application of rich and diverse source of bacteria, 
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                                      Factors Affecting the Performance of Microbial Fuel Cells 
                such  as  wastewater,  activated  sludge,  soil  or  sediments  in  mediator-less  MFCs  is  more 
                advantageous  in  wastewater  treatment  due  to  the  presence  of  different  kinds  of  bacteria 
                including electronics and giving a high power density[Logan, 2009; Mathuriya, 2013]. Table 
                1 presents Redox potential of various reactions in MFC electrodes. 
                                  Table 1 Redox potential of various reactions in MFC electrodes 
                                                                                                 
                2.4. Substrate 
                Great varieties of substrates which have been applied in MFCs vary from simple compounds 
                to  complex  mixtures  of  organic  matters.  In  some  cases,  pure  substrates  such  as  glucose, 
                [Cheng   et   al.,   2006]   acetate,[Cheng   and   Logan,   2007]   butyrate,[Liu   et   al.,   2005] 
                lactate,[Futamata et al., 2013] proteins, cellulose, cysteine, glycine [Chen et al., 2014] and 
                glycerol  were  used.  Acetate  is  anon  fermentable  substrate  and  a  suitable  electron  donor 
                fordissimilatory  iron-reducing  bacterium  which  generate  power  up  to  66%  higher  than 
                butyrate  [Liu  et  al.,  2005].  Among  different  substrates,  wastewater  is  a  sustainable  rich 
                medium which can be treated by MFCs. There are several reports on electricity generation 
                directly  from  complex  organic  wastewater  such  as  municipal,[  Liu  et  al.,  2011]  swine 
                wastewater, [Min et al., 2005] dairy wastewater, [Mardanpour et al., 2012; Venkata Mohan et 
                al., 2010] slaughter house wastewater,[Katuri et al., 2012] rice mill wastewater,[Behera et al., 
                2010] tannery wastewater, [Mathuriya, 2013] cassava mill wastewater,[Kaewkannetra et al., 
                2011]  molasses  wastewater,[Zhang  et  al.,  2009]  refinery  wastewater,[Zhang  et  al.,  2014] 
                brewery  wastewater,[Mshoperi  et  al.,  2011]  winery  wastewater,[Sciarria  et  al.,  2015] 
                chemical  wastewater,[Mohan  et  al.,  2008;  Raghavulu  et  al.,  2009;  Velvizhi  et  al.,  2014] 
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