title: Electrochemical Characterization of a Novel Exoelectrogenic Bacterium Strain SCS5, Isolated from a Mediator-Less Microbial Fuel Cell and Phylogenetically Related to Aeromonas jandaei.
abstract: A facultative anaerobic bacterium, designated as strain SCS5, was isolated from the anodic biofilm of a mediator-less microbial fuel cell using acetate as the electron donor and α-FeOOH as the electron acceptor. The isolate was Gram-negative, motile, and shaped as short rods (0.9-1.3 μm in length and 0.4-0.5 μm in width). A phylogenetic analysis of the 16S rRNA, gyrB, and rpoD genes suggested that strain SCS5 belonged to the Aeromonas genus in the Aeromonadaceae family and exhibited the highest 16S rRNA gene sequence similarity (99.45%) with Aeromonas jandaei ATCC 49568. However, phenotypic, cellular fatty acid profile, and DNA G+C content analyses revealed that there were some distinctions between strain SCS5 and the type strain A. jandaei ATCC 49568. The optimum growth temperature, pH, and NaCl (%) for strain SCS5 were 35°C, 7.0, and 0.5% respectively. The DNA G+C content of strain SCS5 was 59.18%. The isolate SCS5 was capable of reducing insoluble iron oxide (α-FeOOH) and transferring electrons to extracellular material (the carbon electrode). The electrochemical activity of strain SCS5 was corroborated by cyclic voltammetry and a Raman spectroscopic analysis. The cyclic voltammogram of strain SCS5 revealed two pairs of oxidation-reduction peaks under anaerobic and aerobic conditions. In contrast, no redox pair was observed for A. jandaei ATCC 49568. Thus, isolated strain SCS5 is a novel exoelectrogenic bacterium phylogenetically related to A. jandaei, but shows distinct electrochemical activity from its close relative A. jandaei ATCC 49568.
authors.affiliation: Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences.
authors.forename: Subed Chandra Dev
authors.initials: SC
authors.lastname: Sharma
authors.forename: Cuijie
authors.initials: C
authors.lastname: Feng
authors.forename: Jiangwei
authors.initials: J
authors.lastname: Li
authors.forename: Anyi
authors.initials: A
authors.lastname: Hu
authors.forename: Han
authors.initials: H
authors.lastname: Wang
authors.forename: Dan
authors.initials: D
authors.lastname: Qin
authors.forename: Chang-Ping
authors.initials: CP
authors.lastname: Yu
mesh_terms: D000332:Aerobiosis; D000333:Aeromonas / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D000693:Anaerobiosis; D015373:Bacterial Typing Techniques; D001482:Base Composition; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D016000:Cluster Analysis; D003600:Cytosol / Q000737:chemistry; D027081:DNA Gyrase / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D055664:Electrochemical Techniques; D004579:Electron Transport; D005227:Fatty Acids / Q000032:analysis; D005290:Ferric Compounds / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008124:Locomotion; D008854:Microscopy, Electron; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012808:Sigma Factor / Q000235:genetics; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D005290:Ferric Compounds; D012336:RNA, Ribosomal, 16S; D012808:Sigma Factor; C000499:ferric oxide; D012965:Sodium Chloride; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D027081:DNA Gyrase