title: Sulfurifustis variabilis gen. nov., sp. nov., a sulfur oxidizer isolated from a lake, and proposal of Acidiferrobacteraceae fam. nov. and Acidiferrobacterales ord. nov.
abstract: A novel autotrophic bacterium, strain skN76T, was isolated from sediment of a lake in Japan. As sole electron donor to support chemolithoautotrophic growth, the strain oxidized thiosulfate, tetrathionate and elemental sulfur. For growth, the optimum temperature was 42–45 °C and the optimum pH was 6.8–8.2. The cells were Gram-stain-negative, catalase-positive and oxidase-positive. The strain exhibited changes in morphology depending on growth temperature. Cells grown at the optimum temperature were rod-shaped (0.9–3.0 μm long and 0.3–0.5 μm wide), whereas a filamentous form was observed when the strain was cultured at the lowest permissive growth temperatures. The G+C content of genomic DNA was 69 mol%. The major components in the fatty acid profile were C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the closest cultivated relative of strain skN76T was Acidiferrobacter thiooxydans m-1T, with sequence similarity of 93 %. On the basis of its phylogenetic and phenotypic properties, strain skN76T ( = DSM 100313T =  NBRC 110942T) is proposed as the type strain of a novel species of a novel genus, Sulfurifustis variabilis gen. nov., sp. nov. Novel taxa, Acidiferrobacteraceae fam. nov. and Acidiferrobacterales ord. nov., are also proposed to accommodate the genera Acidiferrobacter and Sulfurifustis gen. nov.
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.
authors.forename: Hisaya
authors.initials: H
authors.lastname: Kojima
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Shinohara
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Fukui
mesh_terms: D015373:Bacterial Typing Techniques; D001482:Base Composition; D004269:DNA, Bacterial / Q000235:genetics; D005227:Fatty Acids / Q000737:chemistry; D020563:Gammaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D007564:Japan; D060106:Lakes / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013455:Sulfur / Q000378:metabolism; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D013455:Sulfur