Abstract/Details

Anaerobic metabolism of organic compounds by hyperthermophilic microorganisms


2002 2002

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Abstract (summary)

From the time of their discovery in the early 1980's, hyperthermophilic microorganisms have been at the center of intense research to describe their diversity as well as the extreme geologic environments they inhabit. Although much has been learned about the metabolism of a select few pure culture isolates, very little is known about the great diversity of their metabolic potential, particularly in situ. Recent models for the fate of short-chain organic acids, and presumably aromatics and long-chain fatty acids, indicated that they must diffuse out of hydrothermal environments before being metabolized because no hyperthermophilic microorganisms in pure culture or in actual sediment or rock were known to utilize these substrates. In this study, the metabolism of the key fermentation product, acetate, as well as aromatic compounds was investigated in the hyperthermophilic microorganisms, Ferroglobus placidus and Geoglobus ahangari. In addition, the fate of 14C-radiolabeld organic compounds was evaluated in hydrothermal sediments collected from a shallow marine vent on Vulcano, Italy. F. placidus and G. ahangari grew at 85°C in anaerobic medium with acetate as the sole electron donor and poorly crystalline Fe(III) oxide as the electron acceptor. Additionally, F. placidus was capable of using a variety of aromatic compounds as the sole electron donor for the reduction of Fe(III). In hydrothermal sediments from Vulcano, Italy, the radiolabeled acetate, palmitate, and glucose were completely oxidized to carbon dioxide coupled to sulfate reduction. Radiolabeled L-glutamate and benzoate were primarily oxidized to carbon dioxide, although incompletely. These results are the first indication that complex organic matter can be oxidized to carbon dioxide by hyperthermophilic microorganisms, and thus a complete carbon cycle may be modeled for hydrothermal systems.

Indexing (details)


Subject
Microbiology;
Biogeochemistry
Classification
0410: Microbiology
0425: Biogeochemistry
Identifier / keyword
Earth sciences, Biological sciences, Anaerobic metabolism, Ferroglobus placidus, Geoglobus ahangari, Hyperthermophilic, Microorganisms, Organic compounds
Title
Anaerobic metabolism of organic compounds by hyperthermophilic microorganisms
Author
Tor, Jason M.
Number of pages
190
Publication year
2002
Degree date
2002
School code
0118
Source
DAI-B 63/10, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780493882093, 049388209X
Advisor
Lovley, Derek R.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3068598
ProQuest document ID
305584159
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305584159
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