Bidirectional microbial electron transfer: switching an acetate oxidizing biofilm to nitrate reducing conditions

Up to date a few electroactive bacteria embedded in biofilms are described to catalyze both anodic and cathodic reactions in bioelectrochemical systems (i.e. bidirectional electron transfer). How these bacteria transfer electrons to or from the electrode is still uncertain. In this study the extracellular electron transfer mechanism of bacteria within an electroactive biofilm was investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). First, a mature anodic electroactive biofilm was developed from an activated sludge sample (inoculum), acetate as electron donor and a poised electrode (+397 mV vs. SHE). Later, this biofilm was “switched” to biocathodic conditions by feeding it with a medium containing nitrates and poising the electrode at –303 mV vs. SHE. The electrochemical characterization indicated that both, acetate oxidation and nitrate reduction took place at a similar formal potential of −175±05 and −175±34 mV vs. SHE, respectively. The biofilm was predominantly composed by Geobacter sp. at both experimental conditions. Taken together, the results indicated that both processes could be catalyzed by using the same electron conduit, and most likely by the same bacterial consortium. Hence, this study suggests that electroactive bacteria within biofilms could use the same electron transfer conduit for catalyzing anodic and cathodic reactions.

Additional Info

  • Year: 2016
  • Authors: Narcís Pous, Alessandro A. Carmona-Martínez, Anna Vilajeliu-Pons, Erika Fiset, Lluis Bañeras, Eric Trably, M. Dolors Balaguer, Jesús Colprim, Nicolas Bernet, Sebastià Puig
  • Reference: Biosensors and Bioelectronics, Volume 75, 15 January 2016, Pages 352–358

Search articles

Title

Year

Authors

Laboratory of Chemical and Enviromental Engineering

Institut de Medi Ambient
Universitat de Girona
Campus Montilivi
17003 Girona

Parc Científic i Tecnològic de la UdG
Edifici Jaume Casademont, Porta B
Pic de Peguera, 15
17003 Girona
Tel. +34 972 41 98 59
info@lequia.udg.cat

 

Search

Keyword

Social Media

Follow us on ...

Facebook Twitter Youtube Linkedin

NOTE! This site uses cookies and similar technologies. If you not change browser settings, you agree to it. Cookie Policy