This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Reimers, C. E. Articles by Girguis, P. R. Search for Related Content PubMed PubMed Citation Articles by Reimers, C. E. Articles by Girguis, P. R. Agricola Articles by Reimers, C. E. Articles by Girguis, P. R.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, November 2007, p. 7029-7040, Vol. 73, No. 21
0099-2240/07/$08.00+0     doi:10.1128/AEM.01209-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Substrate Degradation Kinetics, Microbial Diversity, and Current Efficiency of Microbial Fuel Cells Supplied with Marine Plankton

Clare E. Reimers,^1* Hilmar A. Stecher III,¹ John C. Westall,² Yvan Alleau,¹ Kate A. Howell,¹ Leslie Soule,¹ Helen K. White,³ and Peter R. Girguis³

College of Oceanic and Atmospheric Sciences, Hatfield Marine Science Center, Oregon State University, Newport, Oregon 97365,¹ Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331,² Harvard University, Biological Labs, 16 Divinity Avenue, Cambridge, Massachusetts 02138³

Received 30 May 2007/ Accepted 23 August 2007

The decomposition of marine plankton in two-chamber, seawater-filled microbial fuel cells (MFCs) has been investigated and related to resulting chemical changes, electrode potentials, current efficiencies, and microbial diversity. Six experiments were run at various discharge potentials, and a seventh served as an open-circuit control. The plankton consisted of a mixture of freshly captured phytoplankton and zooplankton (0.21 to 1 mm) added at an initial batch concentration of 27.5 mmol liter^–1 particulate organic carbon (OC). After 56.7 days, between 19.6 and 22.2% of the initial OC remained, sulfate reduction coupled to OC oxidation accounted for the majority of the OC that was degraded, and current efficiencies (of the active MFCs) were between 11.3 and 15.5%. In the open-circuit control cell, anaerobic plankton decomposition (as quantified by the decrease in total OC) could be modeled by three terms: two first-order reaction rate expressions (0.79 day^–1 and 0.037 day^–1, at 15°C) and one constant, no-reaction term (representing 10.6% of the initial OC). However, in each active MFC, decomposition rates increased during the third week, lagging just behind periods of peak electricity generation. We interpret these decomposition rate changes to have been due primarily to the metabolic activity of sulfur-reducing microorganisms at the anode, a finding consistent with the electrochemical oxidization of sulfide to elemental sulfur and the elimination of inhibitory effects of dissolved sulfide. Representative phylotypes, found to be associated with anodes, were allied with Delta-, Epsilon-, and Gammaproteobacteria as well as the Flavobacterium-Cytophaga-Bacteroides and Fusobacteria. Based upon these results, we posit that higher current efficiencies can be achieved by optimizing plankton-fed MFCs for direct electron transfer from organic matter to electrodes, including microbial precolonization of high-surface-area electrodes and pulsed flowthrough additions of biomass.

---

* Corresponding author. Mailing address: College of Oceanic and Atmospheric Sciences, Hatfield Marine Science Center, Oregon State University, Newport, OR 97365. Phone: (541) 867-0220. Fax: (541) 867-0138. E-mail: creimers{at}coas.oregonstate.edu

Published ahead of print on 31 August 2007.

---

Applied and Environmental Microbiology, November 2007, p. 7029-7040, Vol. 73, No. 21
0099-2240/07/$08.00+0     doi:10.1128/AEM.01209-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.