Geochip-based functional gene analysis of anodophilic communities in microbial electrolysis cells under different operational modes.

A microbial electrolysis cell (MEC) is a bioelectrochemical system that can produce hydrogen from acetate at high hydrogen recoveries, but the composition and structure of the microbial communities in this system have not been extensively studied. We used a high throughput metagenomics technology (GeoChip) to examine the microbial community functional structure in MECs initially operated under different conditions. We found that startup conditions had little or no effect on reactor performance in terms of Coulombic efficiencies (CEs) and COD removals, somewhat greater effects on CO(2) and CH(4) production, and very large effects on hydrogen production. Hydrogen yields were generally higher for reactors that were always operated as MECs than those initially operated as MFCs. Hydrogen yields were nine times larger for MEC reactors with an applied voltage of 0.7 V (64%∼80% efficiencies) than 0.3 V (<7-8%), independent of startup conditions. GeoChip analysis revealed that the functional and phylogenetic diversity of MEC microbial communities after 4 months was quite high despite the use of only a single substrate (acetate). MECs with the largest hydrogen yields had the highest microbial diversity. Multivariate analyses showed that communities that developed in the MECs were well separated from those present under startup conditions, indicating reactor operation altered microbial community composition. Community shifts based on a Mantel test were significantly related to CEs and COD removals in these reactors, suggesting that there were significant changes in microbial community composition as a result of conditions that affected MEC performance. Common well-known exoelectrogenic bacteria (e.g., Geobacter, Shewanella, Desulfovibrio, and Anaeromyxobacter) were found in these systems, but their importance in determining reactor functional performance was not supported with a high confidence in our statistical analysis.

[1]  Dorothea K. Thompson,et al.  Development and evaluation of microarray-based whole-genome hybridization for detection of microorganisms within the context of environmental applications. , 2004, Environmental science & technology.

[2]  W. Lilly,et al.  Electron transfer in the dissimilatory iron-reducing bacterium Geobacter metallireducens , 2000 .

[3]  Jizhong Zhou.  Microarrays for bacterial detection and microbial community analysis. , 2003, Current opinion in microbiology.

[4]  B. Logan,et al.  Electricity-producing bacterial communities in microbial fuel cells. , 2006, Trends in microbiology.

[5]  A. Beliaev,et al.  MtrC, an outer membrane decahaem c cytochrome required for metal reduction in Shewanella putrefaciens MR‐1 , 2001, Molecular microbiology.

[6]  Derek R Lovley,et al.  Microarray and genetic analysis of electron transfer to electrodes in Geobacter sulfurreducens. , 2006, Environmental microbiology.

[7]  Alice Dohnalkova,et al.  Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[8]  Bruce E Logan,et al.  Hydrogen production in a single chamber microbial electrolysis cell lacking a membrane. , 2008, Environmental science & technology.

[9]  N. Mantel.  The detection of disease clustering and a generalized regression approach. , 1967, Cancer research.

[10]  U von Stockar,et al.  Physiologic studies with the sulfate-reducing bacterium Desulfovibrio desulfuricans: evaluation for use in a biofuel cell. , 1996, Enzyme and microbial technology.

[11]  W. Verstraete,et al.  Metabolites produced by Pseudomonas sp. enable a Gram-positive bacterium to achieve extracellular electron transfer , 2008, Applied Microbiology and Biotechnology.

[12]  Hyung-Sool Lee,et al.  Fate of H2 in an upflow single-chamber microbial electrolysis cell using a metal-catalyst-free cathode. , 2009, Environmental science & technology.

[13]  Christopher W. Schadt,et al.  Microarray-Based Analysis of Subnanogram Quantities of Microbial Community DNAs by Using Whole-Community Genome Amplification , 2006, Applied and Environmental Microbiology.

[14]  B. Logan.  Exoelectrogenic bacteria that power microbial fuel cells , 2009, Nature Reviews Microbiology.

[15]  D. Wardle,et al.  Ecological Linkages Between Aboveground and Belowground Biota , 2004, Science.

[16]  W. Verstraete,et al.  Microbial fuel cells: novel biotechnology for energy generation. , 2005, Trends in biotechnology.

[17]  Bruce E Logan,et al.  Evaluation of catalysts and membranes for high yield biohydrogen production via electrohydrogenesis in microbial electrolysis cells (MECs). , 2009, Water science and technology : a journal of the International Association on Water Pollution Research.

[18]  Jizhong Zhou.  Predictive microbial ecology , 2009, Microbial biotechnology.

[19]  D. R. Bond,et al.  Electricity Production by Geobacter sulfurreducens Attached to Electrodes , 2003, Applied and Environmental Microbiology.

[20]  Byung Hong Kim,et al.  Use of acetate for enrichment of electrochemically active microorganisms and their 16S rDNA analyses. , 2003, FEMS microbiology letters.

[21]  J. Tiedje,et al.  DNA recovery from soils of diverse composition , 1996, Applied and environmental microbiology.

[22]  Jizhong Zhou,et al.  Microarray-Based Characterization of Microbial Community Functional Structure and Heterogeneity in Marine Sediments from the Gulf of Mexico , 2008, Applied and Environmental Microbiology.

[23]  Christopher L. Hemme,et al.  GeoChip 3.0 as a high-throughput tool for analyzing microbial community composition, structure and functional activity , 2010, The ISME Journal.

[24]  W. Verstraete,et al.  Biofuel Cells Select for Microbial Consortia That Self-Mediate Electron Transfer , 2004, Applied and Environmental Microbiology.

[25]  Paul C Mills,et al.  Characterization of an electron conduit between bacteria and the extracellular environment , 2009, Proceedings of the National Academy of Sciences.

[26]  Herbert H. P. Fang,et al.  Fermentative Hydrogen Production From Wastewater and Solid Wastes by Mixed Cultures , 2007 .

[27]  Grigoriy E. Pinchuk,et al.  Towards environmental systems biology of Shewanella , 2008, Nature Reviews Microbiology.

[28]  Bruce E. Logan,et al.  Increased performance of single-chamber microbial fuel cells using an improved cathode structure , 2006 .

[29]  Thomas Mitchell-Olds,et al.  Evolutionary and ecological functional genomics , 2003, Nature Reviews Genetics.

[30]  Adam Kleczkowski,et al.  Biodiversity and ecosystem function in soil , 2005 .

[31]  S. Levin,et al.  Fundamental Questions in Biology , 2006, PLoS biology.

[32]  Bruce E Logan,et al.  Sustainable and efficient biohydrogen production via electrohydrogenesis , 2007, Proceedings of the National Academy of Sciences.

[33]  D. Lovley.  The microbe electric: conversion of organic matter to electricity. , 2008, Current opinion in biotechnology.

[34]  Y. Zuo,et al.  Isolation of the Exoelectrogenic Bacterium Ochrobactrum anthropi YZ-1 by Using a U-Tube Microbial Fuel Cell , 2008, Applied and Environmental Microbiology.

[35]  Benjamin Erable,et al.  Marine aerobic biofilm as biocathode catalyst. , 2010, Bioelectrochemistry.