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Category: Applied and Industrial Microbiology; Environmental Microbiology
Fermentative, Iron-Reducing, and Nitrate-Reducing Microorganisms, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555817589/9781555813277_Chap05-1.gif /docserver/preview/fulltext/10.1128/9781555817589/9781555813277_Chap05-2.gifAbstract:
This chapter focuses on the microbiology of heterotrophic fermentative bacteria, some of which are able to grow by using various electron acceptors such as elemental sulfur, thiosulfate, iron, and nitrate. Clearly, the geochemistry of the reservoirs, together with the mineralogy and the physicochemical conditions of the oil field waters, selects for the presence of specific types of microorganisms. This is true for conditions in oil reservoirs where temperatures commonly between 60 and 80°C affect the survival and/or growth of thermophilic and hyperthermophilic fermentative microorganisms. Mesophilic, thermophilic, and hyperthermophilic fermentative bacteria constitute an important microbial community of the oil field environment. Its physiological and phylogenetic traits were unique among the oil field fermentative isolates, as it used protein extracts such as peptones and amino acids but was unable to ferment sugars. Nitrate-reducing microorganisms from oil reservoirs are of increased interest due to the in situ use of nitrate by oil companies to decrease sulfide concentrations in oil fields. In addition to sulfate-reducing bacteria (SRB) and Methanoarchaea, fermentative bacteria with various metabolic abilities were recovered from oil reservoirs. The presence of both hydrogen and acetate in deep reservoirs may explain survival and/or growth of some thermophilic heterotrophs. Through fermentative and oxidative processes, thermophiles appear metabolically adapted to participate in the energy and carbon cycles of deep reservoirs as proposed by the researchers.
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Phylogenetic dendrogram showing the position of Halanaerobium strains isolated from petroleum reservoirs (boldface) within the order Halanaerobiales. sacch., saccharolyticum. Bar, 10% sequence divergence.
Phylogenetic dendrogram showing the position of Halanaerobium strains isolated from petroleum reservoirs (boldface) within the order Halanaerobiales. sacch., saccharolyticum. Bar, 10% sequence divergence.
Phylogenetic dendrogram showing the position of members of the family of Thermotogaceae isolated from petroleum reservoirs (in boldface type). Numbers on branch nodes are bootstrap values. Bar, 5% sequence divergence.
Phylogenetic dendrogram showing the position of members of the family of Thermotogaceae isolated from petroleum reservoirs (in boldface type). Numbers on branch nodes are bootstrap values. Bar, 5% sequence divergence.
(A) Electron micrograph of Thermotoga elfii strain 6459T showing the typical outer sheath-like structure of Thermotoga. Bar, 1 µm. (B) Transmission electron micrograph of Petrotoga mexicana showing terminal toga. Bar, 2 µm. (C) Phase-contrast photomicrograph of Thermoanaerobacter brockii strain 5268T showing terminal spores. Bar, 10 µm. (D) Scanning electron micrograph of Garciella nitratireducens after thermal stress, showing spherical, terminal spores swelling the cells and a subpolar flagellum. Bar, 1 µm. (Panel A reprinted from Ravot et al. [1995a] with publisher permission. Panel B reprinted from Miranda-Tello et al. [2004] with publisher permission. Panel C reprinted from Cayol et al. [1995] with publisher permission. Panel D reprinted from Miranda-Tello et al. [2003] with publisher permission.)
(A) Electron micrograph of Thermotoga elfii strain 6459T showing the typical outer sheath-like structure of Thermotoga. Bar, 1 µm. (B) Transmission electron micrograph of Petrotoga mexicana showing terminal toga. Bar, 2 µm. (C) Phase-contrast photomicrograph of Thermoanaerobacter brockii strain 5268T showing terminal spores. Bar, 10 µm. (D) Scanning electron micrograph of Garciella nitratireducens after thermal stress, showing spherical, terminal spores swelling the cells and a subpolar flagellum. Bar, 1 µm. (Panel A reprinted from Ravot et al. [1995a] with publisher permission. Panel B reprinted from Miranda-Tello et al. [2004] with publisher permission. Panel C reprinted from Cayol et al. [1995] with publisher permission. Panel D reprinted from Miranda-Tello et al. [2003] with publisher permission.)
Fermentative bacteria isolated from oil field environment a
Fermentative bacteria isolated from oil field environment a
Nitrate and/or iron-reducing bacteria isolated from oilfield environments
Nitrate and/or iron-reducing bacteria isolated from oilfield environments