Article

Geobacter sulfurreducens sp. nov., a hydrogen- and acetate-oxidizing dissimilatory metal-reducing microorganism.

Department of Botany and Microbiology, University of Oklahoma, Norman 73019.
Applied and Environmental Microbiology (Impact Factor: 3.95). 11/1994; 60(10):3752-9.
Source: PubMed

ABSTRACT A dissimilatory metal- and sulfur-reducing microorganism was isolated from surface sediments of a hydrocarbon-contaminated ditch in Norman, Okla. The isolate, which was designated strain PCA, was an obligately anaerobic, nonfermentative nonmotile, gram-negative rod. PCA grew in a defined medium with acetate as an electron donor and ferric PPi, ferric oxyhydroxide, ferric citrate, elemental sulfur, Co(III)-EDTA, fumarate, or malate as the sole electron acceptor. PCA also coupled the oxidation of hydrogen to the reduction of Fe(III) but did not reduce Fe(III) with sulfur, glucose, lactate, fumarate, propionate, butyrate, isobutyrate, isovalerate, succinate, yeast extract, phenol, benzoate, ethanol, propanol, or butanol as an electron donor. PCA did not reduce oxygen, Mn(IV), U(VI), nitrate, sulfate, sulfite, or thiosulfate with acetate as the electron donor. Cell suspensions of PCA exhibited dithionite-reduced minus air-oxidized difference spectra which were characteristic of c-type cytochromes. Phylogenetic analysis of the 16S rRNA sequence placed PCA in the delta subgroup of the proteobacteria. Its closest known relative is Geobacter metallireducens. The ability to utilize either hydrogen or acetate as the sole electron donor for Fe(III) reduction makes strain PCA a unique addition to the relatively small group of respiratory metal-reducing microorganisms available in pure culture. A new species name, Geobacter sulfurreducens, is proposed.

1 Bookmark
 · 
168 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Microbial Fuel Cells (MFC) are bioelectrochemical systems (BES) where at least one of the two redox reactions is catalysed by a biological component (i.e. a whole bacterial cell, an enzyme or a metabolite). The involvement of biological catalysis differentiates them from chemical fuel cells (CFC). BES represents a technology capable to produce power, but also to poise an environmental site at a given redox potential. Moreover, valuable chemicals can be harvested such as hydrogen, methane, organic compounds, hydrogen peroxide or sodium hydroxide. Plenty of other application possibilities for BES have been reported at the level of ‘proof of principle’. Hence, the challenge is to upgrade BES from the lab-scale level to fullscale application and to demonstrate appropriate opportunities in terms of overall economics. Therefore, it is important to find niches where BES technology has clear cut advantages in terms of overall Life Cycle Assessment (LCA) relative to its competitors to turn BES into a mature technology. This chapter reviews recent advantages and challenges of BES from principals to applications.
    Fuel Cell Science and Engineering: Materials, Processes, Systems and Technology, Edited by Detlef Stolten, Bernd Emonts, 04/2012: chapter 6: pages 174-184; Wiley-VCH Verlag & Co. KGaA., ISBN: 9783527650248
  • FEMS Microbiology Letters 01/1999; 176(1):131-138. DOI:10.1016/S0378-1097(99)00229-3 · 2.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Anaerobic respiration with elemental sulfur/polysulfide or organic disulfides is performed by several bacteria and archaea, but has only been investigated in a few organisms in detail. The electron transport chain that catalyzes polysulfide reduction in the Gram-negative bacterium Wolinella succinogenes consists of a dehydrogenase (formate dehydrogenase or hydrogenase) and polysulfide reductase. The enzymes are integrated in the cytoplasmic membrane with the catalytic subunits exposed to the periplasm. The mechanism of electron transfer from formate dehydrogenase or hydrogenase to polysulfide reductase is discussed. The catalytic subunit of polysulfide reductase belongs to the family of molybdopterin-dinucleotide-containing oxidoreductases. From the hyperthermophilic archaeon Pyrodictium abyssi isolate TAG11 an integral membrane complex has been isolated which catalyzes the reduction of sulfur with H2 as electron donor. This enzyme complex, which is composed of a hydrogenase and a sulfur reductase, contains heme groups and several iron-sulfur clusters, but does not contain molybdenum or tungsten. In methanogenic archaea, the heterodisulfide of coenzyme M and coenzyme B is the terminal electron acceptor of the respiratory chain. In methanogens belonging to the order Methanosarcinales, this respiratory chain is composed of a dehydrogenase, the membrane-soluble electron carrier methanophenazine, and heterodisulfide reductase. The catalytic subunit of heterodisulfide reductase contains only iron-sulfur clusters. An iron-sulfur cluster may directly be involved in the reduction of the disulfide substrate.
    FEMS Microbiology Reviews 01/1998; 22(5):353-381. DOI:10.1016/S0168-6445(98)00035-7 · 13.81 Impact Factor

Full-text (2 Sources)

Download
45 Downloads
Available from
May 22, 2014