title: Fully reversible current driven by a dual marine photosynthetic microbial community.
abstract: The electrochemical activity of two seawater microbial consortia were investigated in three-electrode bioelectrochemical cells. Two seawater inocula - from the Sunshine Coast (SC) and Gold Coast (GC) shores of Australia - were enriched at +0.6 V vs. SHE using 12/12 h day/night cycles. After re-inoculation, the SC consortium developed a fully-reversible cathodic/anodic current, with a max. of -62 mA m(-2) during the day and +110 mA m(-2) at night, while the GC exhibited negligible daytime output but +98 mA m(-2) at night. Community analysis revealed that both enrichments were dominated by cyanobacteria, indicating their potential as biocatalysts for indirect light conversion to electricity. Moreover, the presence of γ-proteobacterium Congregibacter in SC biofilm was likely related to the cathodic reductive current, indicating its effectiveness at catalysing cathodic oxygen reduction at a surprisingly high potential. For the first time a correlation between a dual microbial community and fully reversible current is reported.
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Libertus
authors.initials: L
authors.lastname: Darus
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Pablo
authors.initials: P
authors.lastname: Ledezma
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD 4072, Australia.
authors.forename: Jürg
authors.initials: J
authors.lastname: Keller
authors.affiliation: Advanced Water Management Centre, The University of Queensland, St. Lucia, QLD 4072, Australia. Electronic address: s.freguia@awmc.uq.edu.au.
authors.forename: Stefano
authors.initials: S
authors.lastname: Freguia
mesh_terms: D001315:Australia; D001419:Bacteria / Q000378:metabolism; D055162:Biocatalysis; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018441:Biofilms; D004560:Electricity; D055664:Electrochemical Techniques; D004566:Electrodes; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D012623:Seawater / Q000382:microbiology*
chemical_list: D010100:Oxygen
keywords: Biophotovoltaics; Cathodic current; Microbial solar cell; Reversible current; γ-Proteobacterium Congregibacter