Article Quantification of Electron Transfer Rates to a Solid Phase Electron Acceptor through the Stages of Biofilm Formation from Single Cells to Multicellular Communities

Cuantificación de la tasa de transferencia de electrones a un aceptor de electrones de fase sólida a través de las etapas de formación del biofilm de las células individuales de las comunidades multicelulares

Jeffrey S. McLean*^†, Greg Wanger^†, Yuri A. Gorby, Martin Wainstein^†, Jeff McQuaid^†, Shun’ ichi Ishii^†, Orianna Bretschger^†, Haluk Beyenal^‡ and Kenneth H. Nealson^†§

The J. Craig Venter Institute, San Diego, CA, The Gene and Linda Voiland, School of Chemical Engineering and Bioengineering and Center for Environmental, Sediment and Aquatic Research, Washington State University, Pullman, WA, and University of Southern California, Los Angeles, CA

Environ. Sci. Technol., 2010, 44 (7), pp 2721–2727

DOI: 10.1021/es903043p

Publication Date (Web): March 3, 2010

Copyright © 2010 American Chemical Society

Texto completo

Abstract
Microbial fuel cell (MFC) technology has enabled new insights into the mechanisms of electron transfer from dissimilatory metal reducing bacteria to a solid phase electron acceptor. Using solid electrodes as electron acceptors enables quantitative real-time measurements of electron transfer rates to these surfaces. We describe here an optically accessible, dual anode, continuous flow MFC that enables real-time microscopic imaging of anode populations as they develop from single attached cells to a mature biofilms. We used this system to characterize how differences in external resistance affect cellular electron transfer rates on a per cell basis and overall biofilm development in Shewanella oneidensisstrain MR-1. When a low external resistance (100 Ω) was used, estimates of current per cell reached a maximum of 204 fA/cell (1.3 × 106 e− cell−1 sec−1), while when a higher (1 MΩ) resistance was used, only 75 fA/cell (0.4 × 106 e− cell−1 sec−1) was produced. The 1 MΩ anode biomass consistently developed into a mature thick biofilm with tower morphology (>50 μm thick), whereas only a thin biofilm (<5 μm thick) was observed on the 100 Ω anode. These data suggest a link between the ability of a surface to accept electrons and biofilm structure development.