Kamaraj Sathish kumar - Electrical Stress-directed Evolution of Biocatalysts Community Sampled   from A Sodic-saline Soil for Microbial Fuel Cells

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  Publication Details (including relevant citation   information):

  Journal of New Materials for Electrochemical Systems 15, 181-186   (2012)

  © J. New Mat. Electrochem. Systems

  Received: December 07, 2011, Accepted: January 31, 2012,   Available online: April 02, 2012


  Abstract: Anode-respiring bacteria (ARB) perform an unusual form   of respiration in which their electron acceptor is a solid anode.   The

  focus of this study was to characterize the electrical stress   direct evolution of biocatalysts as a way of enriching the   community with ARB

  for microbial fuel cell. The original microbial consortium was   sampled from a sodic-saline bottom soil (Texcoco Lake).   Interestingly, iron

  (III) reducing bacteria consortium in the sodic-saline bottom   soil was 8500 ± 15 MPN/100 mL by the most probable number method,   since

  microbial reduction of iron (III) is reported to be associated to   anode-respiring capabilities. Cyclic voltammetry studies of   electrochemical

  stressed biofilm-ARB were conducted at 28th

  and 135th

  days, and an irreversible electron transfer reaction was found   possibly related to

  electron transfer reaction of the cytochrome. The electrochemical   impedance spectroscopy results revealed that the resistance of   the

  biofilm-ARB decreased with time (28th

  day-11.11Ω and 135th

  day- 5.5Ω), possibly associated to the adaptability of   electroactive biofilm on

  the graphite electrode surface. Confocal microscopy showed that   the biofilms are active in nature and the biofilm-ARB attained   ~40 μm

  thickness at the 136th

  day. Electrical stressed-ARB gave a maximum power density of   79.4mW/m2

  , and unstressed-ARB gave a maximum

  power density of 41.0mW/m2

  in a single-chamber microbial fuel cell (SCMFC). All these   electrochemical experiments and evaluation sug-

  gest that the electrical-stress directed evolution of ARB   community was associated to a more efficient extracellular   electron transfer proc-

  ess in SCMFC.

  Address (URL): http://www.groupes.polymtl.ca/jnmes/modules/journal/index.php/content0748.html