Abstract

We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H 2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen sink at the biofilm anode, methanogenesis, resulted in significant increase in electron recovery as electric current (∼10-12 A/m 2). The presence of acetate at high concentration in the anode compartment and detection of formate, a known intermediate of the acetyl-CoA pathway, provide evidence towards the role of homoacetogenic bacteria. We also assessed the activity of homoacetogens with reverse transcription quantitative PCR targeting formyltetrahydrofolate synthetase (FTHFS) transcripts, and observed a comparable decrease in the FTHFS transcript numbers with current density and acetate concentrations as we decreased the HRT below 4.5 h. The biofilm anode community was predominated by Deltaproteobacteria (70% of total readouts) along with a fraction of the homoacetogenic genus, Acetobacterium (4% of total readouts), established by pyrosequencing targeting the V6 region of the 16S rRNA. Homoacetogens seem to play a major role as syntrophic members of the biofilm anode community when electron recovery is high.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalWater Science and Technology
Volume65
Issue number1
DOIs
StatePublished - 2012

Fingerprint

Electrochemical cells
scavenger
biofilm
Bacteria
Anodes
Biofilms
hydrogen
Hydrogen
bacterium
acetate
targeting
electron
Regenerative fuel cells
methanogenesis
Recovery
electrokinesis
Electrons
Electric currents
Transcription
Current density

Keywords

  • Deep biofilm
  • Formyl tetrahydrofolate synthetase (FTHFS)
  • Homoacetogens

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology

Cite this

@article{f8abe08ed6cb4a53a699a6226d84406b,
title = "The role of homoacetogenic bacteria as efficient hydrogen scavengers in microbial electrochemical cells (MXCs)",
abstract = "We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H 2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen sink at the biofilm anode, methanogenesis, resulted in significant increase in electron recovery as electric current (∼10-12 A/m 2). The presence of acetate at high concentration in the anode compartment and detection of formate, a known intermediate of the acetyl-CoA pathway, provide evidence towards the role of homoacetogenic bacteria. We also assessed the activity of homoacetogens with reverse transcription quantitative PCR targeting formyltetrahydrofolate synthetase (FTHFS) transcripts, and observed a comparable decrease in the FTHFS transcript numbers with current density and acetate concentrations as we decreased the HRT below 4.5 h. The biofilm anode community was predominated by Deltaproteobacteria (70{\%} of total readouts) along with a fraction of the homoacetogenic genus, Acetobacterium (4{\%} of total readouts), established by pyrosequencing targeting the V6 region of the 16S rRNA. Homoacetogens seem to play a major role as syntrophic members of the biofilm anode community when electron recovery is high.",
keywords = "Deep biofilm, Formyl tetrahydrofolate synthetase (FTHFS), Homoacetogens",
author = "Prathap Parameswaran and Cesar Torres and Kang, {Dae Wook} and Bruce Rittmann and Rosa Krajmalnik-Brown",
year = "2012",
doi = "10.2166/wst.2011.519",
language = "English (US)",
volume = "65",
pages = "1--6",
journal = "Water Science and Technology",
issn = "0273-1223",
publisher = "IWA Publishing",
number = "1",

}

TY - JOUR

T1 - The role of homoacetogenic bacteria as efficient hydrogen scavengers in microbial electrochemical cells (MXCs)

AU - Parameswaran, Prathap

AU - Torres, Cesar

AU - Kang, Dae Wook

AU - Rittmann, Bruce

AU - Krajmalnik-Brown, Rosa

PY - 2012

Y1 - 2012

N2 - We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H 2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen sink at the biofilm anode, methanogenesis, resulted in significant increase in electron recovery as electric current (∼10-12 A/m 2). The presence of acetate at high concentration in the anode compartment and detection of formate, a known intermediate of the acetyl-CoA pathway, provide evidence towards the role of homoacetogenic bacteria. We also assessed the activity of homoacetogens with reverse transcription quantitative PCR targeting formyltetrahydrofolate synthetase (FTHFS) transcripts, and observed a comparable decrease in the FTHFS transcript numbers with current density and acetate concentrations as we decreased the HRT below 4.5 h. The biofilm anode community was predominated by Deltaproteobacteria (70% of total readouts) along with a fraction of the homoacetogenic genus, Acetobacterium (4% of total readouts), established by pyrosequencing targeting the V6 region of the 16S rRNA. Homoacetogens seem to play a major role as syntrophic members of the biofilm anode community when electron recovery is high.

AB - We evaluated the consumption of hydrogen gas at the anode of a microbial electrolysis cell (MEC) and characterized the significance of new interactions between anode respiring bacteria (ARB) and homo-acetogens. We demonstrated the significance of biofilm limitation for direct consumption of H 2 over acetate by ARB, using the deep biofilm model. Selective inhibition of the major competing hydrogen sink at the biofilm anode, methanogenesis, resulted in significant increase in electron recovery as electric current (∼10-12 A/m 2). The presence of acetate at high concentration in the anode compartment and detection of formate, a known intermediate of the acetyl-CoA pathway, provide evidence towards the role of homoacetogenic bacteria. We also assessed the activity of homoacetogens with reverse transcription quantitative PCR targeting formyltetrahydrofolate synthetase (FTHFS) transcripts, and observed a comparable decrease in the FTHFS transcript numbers with current density and acetate concentrations as we decreased the HRT below 4.5 h. The biofilm anode community was predominated by Deltaproteobacteria (70% of total readouts) along with a fraction of the homoacetogenic genus, Acetobacterium (4% of total readouts), established by pyrosequencing targeting the V6 region of the 16S rRNA. Homoacetogens seem to play a major role as syntrophic members of the biofilm anode community when electron recovery is high.

KW - Deep biofilm

KW - Formyl tetrahydrofolate synthetase (FTHFS)

KW - Homoacetogens

UR - http://www.scopus.com/inward/record.url?scp=84855884206&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84855884206&partnerID=8YFLogxK

U2 - 10.2166/wst.2011.519

DO - 10.2166/wst.2011.519

M3 - Article

VL - 65

SP - 1

EP - 6

JO - Water Science and Technology

JF - Water Science and Technology

SN - 0273-1223

IS - 1

ER -