Microbial fuel cells prepared with Rio de la Plata river freshwater sediments. Current production and its relationship to changes at anodophilic microbial community

SACCO, N.; PATACCINI, GABRIELA; BONETTO, M. C.; FIGUEROLA, EVA; CORTÓN, EDUARDO

Congreso; 3rd International Microbial Fuel Cell Conference; 2011

Wetsus

Microbial fuel cells prepared with Rio de la Plata river freshwater sediments. Current production and its relationship to changes at anodophilic microbial community. Sacco, Natalia J1,2; Pataccini, Gabriela1; Bonetto, Maria Celina1,2; Figuerola, Eva3 Cortón, Eduardo1,2 1-Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires- Pab. II,  Ciudad Universitaria,  Buenos Aires (C1428EGA) Argentina, 2- CONICET. 3- INGEBI-CONICET, Vuelta de Obligado 2490, Buenos Aires (C1428ADN), Argentina E-mail nsacco@qb.fcen.uba.ar  In a Microbial Fuel Cell (MFC) microorganisms are used to generate an electrical current. At the anodic compartment, the bacteria oxidize organic matter and in some way, electrons are transfer to the anode. An external circuit (which may or may not contain a load resistance, RL) leads the electrons to the cathode, originating an electrical current. The operating principles of a “Sedimentary Microbial Fuel Cell” (SMFC) is simple; while an anode is embedded in anaerobic sediment (marine sediment, river, rice paddies and other aquatic environments rich in organic matter) a cathode is exposed in the aqueous phase over the sediment usually saturated with oxygen.The SMFC have some operational and technological advantagesover most currently processes used for the production of bioenergy. The main application described in literature for SMFC is as a remote power source, long-term power source for autonomous sensors and communication devices. In this work two types of graphite electrodes have been examined in a lab-scale SMFC: disk carbon and graphite reinforced carbon electrodes (called rod electrodes). Three SMFCs were prepared with different characteristics: SM1: sediment +sodium acetate; SM2: sediment without addition, SM3: sediment + formaldehyde. This allowed us to study the effect of theaddition of an externalcarbon source and type of electrode. Voltage, current and maximum power density (PD max) was continuously measured. Analysis was by denaturing gradient gel electrophoresis (DGGE) and scanning electron microscopy (SEM) to analyze the native bacterial communities in sediments and study their development as the SMFC matured. SM1 with disk electrodereached a maximum current density (Jmax) of 27.10 ± 0.13 mA/m2 at 22 days of starting experience. Current density was maintainedat average of 4mA/m2 and PDmax was 8.72± 1.39 mW/m2.  For rod electrodes the values obtained was 70.05 ± 2.12 mA/m2 at 36 days, staying in 9 mA/m2 on average, and the PDmax was 13.93 ± 3.87 mW/m2. The maximum power density obtained for SM2 was approx. 19 mW/ m2 using rod electrodes and approx. 12 mW/ m2 for disk electrodes. With SM3fuel cell, control of “non-current” the PDmax reached during the entire experiment was 0.20 ± 0.02 mW/m2 .