title: Anode potential influences the structure and function of anodic electrode and electrolyte-associated microbiomes.
abstract: Three bioelectrochemical systems were operated with set anode potentials of +300 mV, +550 mV and +800 mV vs. Standard Hydrogen Electrode (SHE) to test the hypothesis that anode potential influences microbial diversity and is positively associated with microbial biomass and activity. Bacterial and archaeal diversity was characterized using 16 S rRNA gene amplicon sequencing, and biofilm thickness was measured as a proxy for biomass. Current production and substrate utilization patterns were used as measures of microbial activity and the mid-point potentials of putative terminal oxidases were assessed using cyclic voltammetry. All measurements were performed after 4, 16, 23, 30 and 38 days. Microbial biomass and activity differed significantly between anode potentials and were lower at the highest potential. Anodic electrode and electrolyte associated community composition was also significantly influenced by anode potential. While biofilms at +800 mV were thinner, transferred less charge and oxidized less substrate than those at lower potentials, they were also associated with putative terminal oxidases with higher mid-point potentials and generated more biomass per unit charge. This indicates that microbes at +800 mV were unable to capitalize on the potential for additional energy gain due to a lack of adaptive traits to high potential solid electron acceptors and/or sensitivity to oxidative stress.
authors.affiliation: School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.|Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Dennis
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Centre for Microbial Electrochemical Systems, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Bernardino
authors.initials: B
authors.lastname: Virdis
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Inka
authors.initials: I
authors.lastname: Vanwonterghem
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Alif
authors.initials: A
authors.lastname: Hassan
authors.affiliation: Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Phil
authors.initials: P
authors.lastname: Hugenholtz
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Australian Centre for Ecogenomics, The University of Queensland, Brisbane, Queensland 4072, Australia.
authors.forename: Gene W
authors.initials: GW
authors.lastname: Tyson
authors.affiliation: Advanced Water Management Centre, The University of Queensland, Brisbane, Queensland 4072, Australia.|Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653 9000 Ghent, Belgium.
authors.forename: Korneel
authors.initials: K
authors.lastname: Rabaey
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018441:Biofilms / Q000254:growth & development*; D004566:Electrodes; D019766:Genes, Archaeal; D005798:Genes, Bacterial; D064307:Microbiota; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D012336:RNA, Ribosomal, 16S