Methanogenium frigidum sp. nov. was isolated from the perennially cold, anoxic hypolimnion of Ace Lake in the Vesfold Hills of Antarctica. The cells were psychrophilic, exhibiting most rapid growth at 15°C and no growth at temperatures above 18 to 20°C. The cells were irregular, nonmotile coccoids (diameter, 1.2 to 2.5 μm) that occurred singly and grew by CO2 reduction by using H2 as a reductant. Formate could replace H2, but growth was slower. Acetate, methanol, and trimethylamine were not catabolized. Cells grew with acetate as the only organic compound in the culture medium, but growth was much faster in medium also supplemented with peptones and yeast extract. The cells were slightly halophilic; good growth occurred in medium supplemented with 350 to 600 mM Na+, but no growth occurred with 100 or 850 mM Na+. The PH range for growth was 6.5 to 7.9; no growth occurred at pH 6.0 or 8.5. Growth was slow (maximum specific growth rate, 0.24 day-1; doubling time, 2.9 days). This is the first report of a psychrophilic methanogen growing by CO2 reduction.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Microbiology
Research Field:	Bacteriology
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
Author:	Franzmann, PD (Dr Franzmann)
ID Code:	10402
Year Published:	1997
Web of Science® Times Cited:	118
Deposited By:	Agricultural Science
Deposited On:	1997-08-01
Last Modified:	2011-08-11
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