State of art of microbial fuel cell in renewable energy resources and its energy harvesting scheme Rajkumar Nagar 1 , Gourav Arya 2 , D.K.Yadav 3 1&2 M.Tech scholar, 3 Associate Professor, EE Department, University College Of Engineering, RTU, KOTA dhamrodiya@gmail.com, aryagourav88@gmail.com, dky.addu@gmail.com Abstract-This paper review the key role of microbial fuelcells(MFC) in renewable energy. It is well known that the conventional sources are not sufficient to meet the present load demands. It became essential to utilize renewable sourcesof energy. Microbial fuel cell is a novel technology for sustainable energy generation. Microbial fuel cells are very interesting in the field of renewable energy because bacteria in indigenous microorganisms or waste water can produce enough electricity to power small devices. This paper describes an MFC energy harvesting scheme using a hysteresis controller and two layers of DC/DC converters. Index Terms- Microbial fuel cell (MFC),Energy harvesting, DC/DC converter. I. INTRODUCTION The global challenge of fossil fuel has made the research into alternative energy sources a widely studied area. One of the attractive alternatives is a microbial fuel cell (MFC), which converts chemical energy into electrical form through the catabolism of bacteria. Most MFCs are in macro-sized forms that serve as prototypes of large power sources or energy-efficient wastewater treatment technology. Recent activities are to miniaturize MFCs for portable power sources. A miniaturized MFC has demonstrated a power density of the 2 and is able to produce a power of [5-7]. With such power capability, the MFC could supply low power electronic devices and enable wide applications including wireless sensor networks and implantable micro- devices. Direct powering low power devices with a MFC imposesseveral challenges. The typical output voltage of a MFC is less than 0.7 V and is load dependent [9]. To address the challenges, a DC-DC converter is needed to interface between the MFC and the low power electronics. The converter is required to boost its output to the value at which electronic devices can work with and to have high Research has been done that, an efficient MFC energy harvesting system using two layers of DC-DC converters is presented. The proposed system can capture the energy from multiple MFCs at individually controlled operating points and at the same time forms the energy into a usable shape. This paper presents the detail study of the research carried out in this field by different researchers found in the literature. II. MICROBIAL FUEL CELL A microbial fuel cell [Microbial Fuel Cell] is a biological reactor that turns chemical energy present in the bonds of organic compounds into electric energy, through the reactions of microorganism in aerobic conditions. Figure 1.A schematic diagram representing a two chamber microbial fuel cell. Microbial fuel cell consists of anode and cathode, connected by an external circuit and separated by Proton Exchange Membrane. Anodic material must be conductive, bio compatible, and chemically stable with substrate. Metal anodes consisting of noncorrosive stainless steel mesh can be utilized, but copper is not useful due to the toxicity of even trace copper ions to bacteria. The simplest materials for anode electrodes are graphite plates or rods as they are relatively inexpensive, easy to handle, and have a defined surface area. Much larger surface areas are achieved with graphite felt electrodes The most versatile electrode material is carbon, available as compact graphite plates, rods, or granules, as fibrous material (felt, cloth, paper, fibers, foam), and as glassy carbon Proton Exchange Membrane is usually made up of NAFION or ULTREX. Microbial Fuel Cells utilize microbial communities to degrade organics found within wastewater and theoretically in any organic waste product; converting stored chemical energy to electrical energy in a single step. Oxygen is most suitable electron acceptor for an microbial fuel cell due to its high oxidation potential, availability, sustainability and lack of chemical waste product, as the only end product is water. Ifacetate is used as substrate, following reaction takes place: Þ¿´ Õ®·¸²¿ ײ¬·¬«¬» ±º Ì»½¸²±´±¹§ô ×ÐÝóïëô Î××ÝÑ ×²¬·¬«¬·±²¿´ ß®»¿ô Õ±¬¿ øο¶¿¬¸¿²÷ øײ¼·¿÷ ©©©ò¾µ·¬µ±¬¿ò½±³ Ю±½»»¼·²¹ ±º ì ¬¸ ײ¬»®²¿¬·±²¿´ ½±²º»®»²½» ±² ß¼ª¿²½» Ì®»²¼ ·² Û²¹·²»»®·²¹ô Ì»½¸²±´±¹§ ¿²¼ λ»¿®½¸Œ ø×ÝßÌÛÌÎóîðïë÷ Ü¿¬»æ ïç ¬¸ óî𠬸 Ö«²» îðïë ×ÍÞÒæ çéèóèïóçíðèîíóðóð Þ¿´ Õ®·¸²¿ ײ¬·¬«¬» ±º Ì»½¸²±´±¹§ô ×ÐÝóïëô Î××ÝÑ ×²¬·¬«¬·±²¿´ ß®»¿ô Õ±¬¿ øο¶¿¬¸¿²÷ øײ¼·¿÷ ©©©ò¾µ·¬µ±¬¿ò½±³ Ю±½»»¼·²¹ ±º ì ¬¸ ײ¬»®²¿¬·±²¿´ ½±²º»®»²½» ±² ß¼ª¿²½» Ì®»²¼ ·² Û²¹·²»»®·²¹ô Ì»½¸²±´±¹§ ¿²¼ λ»¿®½¸Œ ø×ÝßÌÛÌÎóîðïë÷ Ü¿¬»æ ïç ¬¸ óî𠬸 Ö«²» îðïë ×ÍÞÒæ çéèóèïóçíðèîíóðóð 417