Dissolved oxygen (DO) at cathodic interface is a critical factor influencing microbial fuel cells (MFC) performance. In this work, three MFCs were operated with cathode under different DO conditions: i) air-breathing (A-MFC); ii) water-submerged (W-MFC) and iii) assisted by photosynthetic microorganisms (P-MFC). A plateau of maximum current was reached at 1.06 +/- 0.03 mA, 1.48 +/- 0.06 mA and 1.66 +/- 0.04 mA, increasing respectively for W-MFC, P-MFC and A-MFC. Electrochemical and microbiological tools (Illumina sequencing, confocal microscopy and biofilm cryosectioning) were used to explore anodic and cathodic biofilm in each MFC type. In all cases, biocathodes improved oxygen reduction reaction (ORR) as compared to abiotic condition and A-MFC was the best performing system. Photosynthetic cultures in the cathodic chamber supplied high DO level, up to 16 mg(O2) L-1, which sustained aerobic microbial community in P-MFC biocathode. Halomonas, Pseudomonas and other microaerophilic genera reached > 50% of the total OTUs. The presence of sulfur reducing bacteria (Desulfuromonas) and purple non-sulfur bacteria in A-MFC biocathode suggested that the recirculation of sulfur compounds could shuttle electrons to sustain the reduction of oxygen as final electron acceptor. The low DO concentration limited the cathode in W-MFC A model of two different possible microbial mechanisms is proposed which can drive predominantly cathodic ORR.

Influences of dissolved oxygen concentration on biocathodic microbial communities in microbial fuel cells / L. Rago, P. Cristiani, F. Villa, S. Zecchin, A. Colombo, L. Cavalca, A. Schievano. - In: BIOELECTROCHEMISTRY. - ISSN 1567-5394. - 116(2017 Aug), pp. 39-51. [10.1016/j.bioelechem.2017.04.001]

Influences of dissolved oxygen concentration on biocathodic microbial communities in microbial fuel cells

L. Rago
Primo
;
F. Villa;S. Zecchin;A. Colombo;L. Cavalca;A. Schievano
2017

Abstract

Dissolved oxygen (DO) at cathodic interface is a critical factor influencing microbial fuel cells (MFC) performance. In this work, three MFCs were operated with cathode under different DO conditions: i) air-breathing (A-MFC); ii) water-submerged (W-MFC) and iii) assisted by photosynthetic microorganisms (P-MFC). A plateau of maximum current was reached at 1.06 +/- 0.03 mA, 1.48 +/- 0.06 mA and 1.66 +/- 0.04 mA, increasing respectively for W-MFC, P-MFC and A-MFC. Electrochemical and microbiological tools (Illumina sequencing, confocal microscopy and biofilm cryosectioning) were used to explore anodic and cathodic biofilm in each MFC type. In all cases, biocathodes improved oxygen reduction reaction (ORR) as compared to abiotic condition and A-MFC was the best performing system. Photosynthetic cultures in the cathodic chamber supplied high DO level, up to 16 mg(O2) L-1, which sustained aerobic microbial community in P-MFC biocathode. Halomonas, Pseudomonas and other microaerophilic genera reached > 50% of the total OTUs. The presence of sulfur reducing bacteria (Desulfuromonas) and purple non-sulfur bacteria in A-MFC biocathode suggested that the recirculation of sulfur compounds could shuttle electrons to sustain the reduction of oxygen as final electron acceptor. The low DO concentration limited the cathode in W-MFC A model of two different possible microbial mechanisms is proposed which can drive predominantly cathodic ORR.
Biocathode; Illumina 16S rRNA sequencing; Spirulina; Electroactive biofilms; Oxygen reduction reaction ORR
Settore AGR/16 - Microbiologia Agraria
ago-2017
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/501589
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