Draft Genome Sequences of Methanoculleus horonobensis Strain JCM 15517, Methanoculleus thermophilus Strain DSM 2373, and Methanofollis ethanolicus Strain JCM 15103, Hydrogenotrophic Methanogens Belonging to the Family Methanomicrobiaceae.

The familyMethanomicrobiaceaecomprises hydrogen- and formate-utilizing methanogens. Genome sequencing of nine species ofMethanomicrobiaceaehas been conducted so far. Here, we report three additional draft genome sequences ofMethanomicrobiaceae, those ofMethanoculleus horonobensisJCM 15517 (=T10(T)),Methanoculleus thermophilusDSM 2373 (=CR-1(T)), andMethanofollis ethanolicusJCM 15103 (=HASU(T)).

GENOME ANNOUNCEMENT

Members of the family Methanomicrobiaceae in the phylum Euryarchaeota are known to contain hydrogen- and formate-utilizing methane-producing archaea (1). Some of the known species of this family can also use a secondary alcohol (such as ethanol, 1-propanol, and 1-butanol) as a methanogenic substrate. Currently, complete or draft genome sequences are available for nine species of Methanomicrobiaceae (2–6). To compare the genomic features of Methanomicrobiaceae species, we additionally sequenced three genomes, those of Methanoculleus horonobensis strain JCM 15517 T (=strain T10T), Methanoculleus thermophilus strain DSM 2373 (=CR-1T), and Methanofollis ethanolicus strain JCM 15103T (=HASUT). These strains were isolated from a variety of methanogenic ecosystems: strain T10T was isolated from a groundwater sample collected from a deep diatomaceous shale formation (7), strain CR-1T was isolated from coastal sediment underlying high-temperature effluent from nucleic power plants (8), and strain HASUT was isolated from a mud sample from a lotus field (9). Such ecological diversification may affect the genomic features involved in methanogenesis and interaction with syntrophic metabolizers (syntrophs).

Strains T10T and HASUT were provided by the RIKEN BRC through the National Bio-Resource Project of the MEXT, Japan. Strain CR-1T was provided by Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ), Germany. Whole-genome shotgun sequencing was conducted using the Illumina MiSeq platform (Illumina, San Diego, CA, USA) at the Fasmac Co., Ltd. (Atsugi, Japan). We constructed and sequenced paired-end libraries (4,506,900, 5,396,179, and 9,926,795 bp for T10T, CR-1T, and HASUT, respectively) on the MiSeq. Assembly of the output reads was performed using a SPAdes software version 3.5.0 (10), and the assembled data provide >1,000× coverage of each genome. The draft genome sequences of strains T10T, CR-1T, and HASUT are composed of a total of 15, 24, and 3 scaffolds, have a G+C content of 62.0, 59.3, and 60.3%, estimated genome sizes of 2.49, 2.22, and 2.75 Mb, and 2,430, 2,249, and 2,651 protein-coding genes with function prediction annotated by the Prokka pipeline (11), respectively. Further attempts to identify hydrogenotrophic methanogenesis pathways and energy conservation systems for comparison with the genomes of other Methanomicrobiaceae methanogens are now in progress.

Nucleotide sequence accession numbers.

This draft genome sequence has been deposited at DDBJ/GenBank/EMBL under the accession numbers BCNY01000001 to BCNY01000015 for M. horonobensis strain JCM 15517, BCNX01000001 to BCNX01000023 for M. thermophilus strain DSM 2373, and BCNW01000001 to BCNW01000003 for M. ethanolicus strain JCM 15103.