Recent advances and challenges in the anode architecture and their modifi cations for the applications of microbial fuel cells G. Gnana kumar a,n, V.G. Sathiya Sarathia, Kee Suk Nahmb,nn aDepartment of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai-625 021, Tamilnadu, India bSchool of Chemical Engineering and Department of Energy Storage and Conversion Engineering, Chonbuk National University, Jeonju- 561-756, Republic of Korea a r t i c l e i n f o Article history: Received 4 October 2012 Received in revised form 17 December 2012 Accepted 20 December 2012 Available online 4 January 2013 Keywords: Bio fi lm Charge transfer Compatibility Conductivity Resistance Surface area a b s t r a c t Microbial fuel cells (MFC), the ergonomic technology connects the liaison of fuel cell architecture and biological resources. Many viable applications like wastewater treatment, biosensors and bioremedia- tion can be made possible with the help of MFCs. This technology is still at its toddler stage and immense works are still in progress to increase the volumetric energy density of MFCs. The overall performance of MFC depends on the cardinal part of the system; anode. A number of anode materials are currently in research to adjudge the better one in terms of the startup time, power output and durability. A wide range of possibilities are now currently available in the fabrication and modifi cation of anode materials to substantially increase the power performances. This review adumbrates the signifi cant requirements of anodes that are essential to be fulfi lled, encompasses the aspiring research efforts which have been devoted so far in the anode modifi cation and fabrication strategies to increase the power output, durability and compatibility of the anode interface with the inoculated microorgan- isms. fax: 82 63 270 2306. E-mail addresses: kumarg2006 (G.G. kumar), nahmksjbnu.ac.kr (K.S. Nahm). Biosensors and Bioelectronics 43 (2013) 461475 Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474 1. Introduction Minimization of fossil fuel utilization via green energy genera- tion is a major concern of the present generation in which the signifi cance of fuel cells is highly vibrant. Fuel cells serve as alternatives of conventional combustion engines (Olah, 2005) and are presently active in automobiles and domestic power genera- tion. Fuel cells run on hydrogen or hydrogen rich fuel and oxygen with the zero emission profi le. Though the hydrogen powered fuel cells could harvest high electric power with zero emission profi le, the production of hydrogen is at high stakes due to the unavail- ability of its natural existences in a usable form. The term Green energy holds good only if the fuel to process the fuel cell itself is renewable (Borchers et al., 2007; Hansen et al., 2000). In addition, hydrogen fuel cells exhibit certain bottlenecks such as need of precious metal catalysts for the oxidation of fuels (Park et al., 2000; Steele and Heinzel, 2001), requirement of sophisticated environ- ments (Turner, 2007), safe hydrogen storage (Ross, 2006) etc., which not only hamper the commercialization of fuel cells and also the dream of a green world. The said bottlenecks opened the gates of MFCthe next level of green energy device to generate clean energyfromthesustainablefuelsources.MFCisabio- electrochemical system which derives a current through the catalytic activity of micro-organisms. The direct conversion of electrical energy from chemical energy boosts the MFC energy conversion effi ciency over the internal combustion engines (Fig. 1) with a great environmental concern (Behera et al., 2010; Chow et al., 2003; Ediger and Kentel, 1999; Logan et al., 2008; Logan, 2009). MFCs have not only been considered as a superior renew- able energy source over the other fuel cell types and also of other renewable energy sources. Though solar cells are helpful in meet- ing the daytime energy needs, it cannot serve as a primary energy source throughout the day and night without the energy storage devices and its utilization is completely ruled out during winter season and in polar regions. The recharging technology, heavy metal content utilization and need of electricity for charging faded the hope on conventional batteries. The biogas and hydrogen gas production from microbiological conversion of organics compels the reformation of a gas. The overall conversion effi ciency of organic waste to electricity via bio-ethanol is low (1025%) which necessitates the blending of gasoline. The bottlenecks of wind turbi