Methanocella paludicola gen. nov., sp. nov., a methane-producing archaeon, the first isolate of the lineage 'Rice Cluster I', and proposal of the new archaeal order Methanocellales ord. nov

Sanae Sakai, Hiroyuki Imachi, Satoshi Hanada, Akiyoshi Ohashi, Hideki Harada, Yoichi Kamagata

Research output: Contribution to journalArticle

147 Citations (Scopus)

Abstract

A novel mesophilic, hydrogenotrophic methanogen, strain SANAET, was isolated from an anaerobic, propionate-degrading enrichment culture, which was originally established from rice paddy soil. The cells were non-motile, Gram-negative and rod-shaped (1.8-2.4 mm long by 0.3-0.6 μm wide). Growth of strain SANAET was observed at 25-40 °C, with an optimum temperature range for growth of 35*37 °C. The pH range for growth was 6.5-7.8, with an optimum at pH 7.0. The salinity range for growth was 0-1 g NaCll-1 (0-17 mM). The isolate was able to utilize H2/CO2 and formate for growth and methane production. The G+C content of the genomic DNA was 56.6 mol%. Based on comparative 16S rRNA gene sequence analysis, strain SANAET was affiliated with a clone lineage of the Archaea, Rice Cluster I (RC-I), placing it between the orders Methanosarcinales and Methanomicrobiales within the class 'Methanomicrobia'. 16S rRNA gene sequence similarities between strain SANAET and members of Methanosarcinales were in the range 80.0-82.8 %, and those between the strain and members of Methanomicrobiales ranged from 77.5 to 82.4 %. In addition to 16S rRNA gene analysis, sequence analysis of the mcrA gene (encoding the a subunit of methyl-coenzyme M reductase, a key enzyme in the methane production pathway) also showed that strain SANAET was affiliated with the RC-I lineage. Here, we propose the name Methanocella paludicola gen. nov., sp. nov. for the isolate, the first of the RC-I lineage. The type strain is SANAET (=JCM 13418T=NBRC 101707T=DSM 17711T). In addition, we also propose the status of order for the RC-I lineage, for which we propose the name Methanocellales ord. nov.

Original languageEnglish
Pages (from-to)929-936
Number of pages8
JournalInternational journal of systematic and evolutionary microbiology
Volume58
Issue number4
DOIs
Publication statusPublished - 2008 Apr 1

ASJC Scopus subject areas

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics

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