Isolation of a Methanogen from Deep Marine Sediments That Contain Methane Hydrates, and Description of <i>Methanoculleus submarinus</i> sp. nov

• Jill A. Mikucki

  Biology Department, Portland State University, Portland, Oregon

• Yitai Liu

  Biology Department, Portland State University, Portland, Oregon

• Mark Delwiche

  Idaho National Environmental and Engineering Laboratory, Idaho Falls, Idaho

• Frederick S. Colwell

  Idaho National Environmental and Engineering Laboratory, Idaho Falls, Idaho

• David R. Boone

  Biology Department, Portland State University, Portland, Oregon

Abstract

We isolated a methanogen from deep in the sediments of the Nankai Trough off the eastern coast of Japan. At the sampling site, the water was 950 m deep and the sediment core was collected at 247 m below the sediment surface. The isolated methanogen was named Nankai-1. Cells of Nankai-1 were nonmotile and highly irregular coccoids (average diameter, 0.8 to 2 μm) and grew with hydrogen or formate as a catabolic substrate. Cells required acetate as a carbon source. Yeast extract and peptones were not required but increased the growth rate. The cells were mesophilic, growing most rapidly at 45°C (no growth at ≤10°C or ≥55°C). Cells grew with a maximum specific growth rate of 2.43 day −1 at 45°C. Cells grew at pH values between 5.0 and 8.7 but did not grow at pH 4.7 or 9.0. Strain Nankai-1 grew in a wide range of salinities, from 0.1 to 1.5 M Na + . The described phenotypic characteristics of this novel isolate were consistent with the in situ environment of the Nankai Trough. This is the first report of a methanogenic isolate from methane hydrate-bearing sediments. Phylogenetic analysis of its 16S rRNA gene sequence indicated that it is most closely related to Methanoculleus marisnigri (99.1% sequence similarity), but DNA hybridization experiments indicated a DNA sequence similarity of only 49%. Strain Nankai-1 was also found to be phenotypically similar to M. marisnigri , but two major phenotypic differences were found: strain Nankai-1 does not require peptones, and it grows fastest at a much higher temperature. We propose a new species, Methanoculleus submarinus , with strain Nankai-1 as the type strain.

Journal

• Applied and Environmental Microbiology

  Applied and Environmental Microbiology 69 (6), 3311-3316, 2003-06

  American Society for Microbiology

Keywords

• Ecology
• Applied Microbiology and Biotechnology
• Food Science
• Biotechnology

Details

• CRID: 1360292621304594560
• NII Article ID: 80016018117
• DOI: 10.1128/aem.69.6.3311-3316.2003
• ISSN: 10985336
• ISSN: 00992240
• Web Site: https://journals.asm.org/doi/pdf/10.1128/AEM.69.6.3311-3316.2003
• Data Source:
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  • CiNii Articles