title: Methanohalophilus levihalophilus sp. nov., a slightly halophilic, methylotrophic methanogen isolated from natural gas-bearing deep aquifers, and emended description of the genus Methanohalophilus.
abstract: A mesophilic, slightly halophilic, obligately methylotrophic, methanogenic archaeon, designated strain GTA13(T), was isolated from natural gas-bearing confined aquifers in the Minami-Kanto gas field, Japan. The cells were non-motile, slightly irregular cocci, 0.7-1.0 µm in diameter and occurred singly, in pairs or as small aggregates. The cells grew with tri- or dimethylamine but not with H2/CO2, formate, acetate, methanol or dimethyl sulphide. Vitamins, sodium and magnesium were required for growth. Optimal growth occurred at pH 7.0-7.5, 35 °C, 0.35-0.40 M NaCl and 15-50 mM MgCl2. The NaCl range for growth was 0.2-1.3 M. The DNA G+C content was 43.7 mol%. Strain GTA13(T) showed highest levels of 16S rRNA gene sequence similarity with Methanohalophilus portucalensis FDF-1(T) (96.4% sequence similarity) and Methanohalophilus halophilus DSM 3094(T) (96.0%). On the basis of physiological and phylogenetic features, strain GTA13(T) is considered to represent a novel species of the genus Methanohalophilus, for which the name Methanohalophilus levihalophilus sp. nov. is proposed. The type strain is GTA13(T) ( = NBRC 110099(T) = DSM 28452(T)). An emended description of the genus Methanohalophilus is also proposed.
authors.affiliation: Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Taiki
authors.initials: T
authors.lastname: Katayama
authors.affiliation: Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Yoshioka
authors.affiliation: Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Mochimaru
authors.affiliation: Bioproduction Research Institute, AIST, 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Xian-Ying
authors.initials: XY
authors.lastname: Meng
authors.affiliation: Kanto Natural Gas Development Co., Ltd, 661 Mobara, Mobara, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Muramoto
authors.affiliation: Kanto Natural Gas Development Co., Ltd, 661 Mobara, Mobara, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Usami
authors.affiliation: Kanto Natural Gas Development Co., Ltd, 661 Mobara, Mobara, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Bioproduction Research Institute, AIST, 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kamagata
authors.affiliation: Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Sakata
mesh_terms: D001482:Base Composition; D019641:DNA, Archaeal / Q000235:genetics; D060587:Groundwater / Q000382:microbiology*; D007564:Japan; D000432:Methanol; D017019:Methanosarcinaceae / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D059206:Natural Gas / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D019641:DNA, Archaeal; D059206:Natural Gas; D012336:RNA, Ribosomal, 16S; D000432:Methanol