Sulfurifustis variabilis gen. nov., sp. nov., a sulfur oxidizer isolated from a lake, and proposal of Acidiferrobacteraceae fam. nov. and Acidiferrobacterales ord. nov.

Abstract

Sulfurifustis variabilis gen. nov., sp. nov., a sulfur oxidizer isolated from a lake, and proposal of Acidiferrobacteraceae fam. nov. and Acidiferrobacterales ord. nov. A novel autotrophic bacterium, strain skN76 T , 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 8C and the optimum pH was 6.8-8.2. The cells were Gram-stain-negative, catalase-positive and oxidasepositive. The strain exhibited changes in morphology depending on growth temperature. Cells grown at the optimum temperature were rod-shaped (0.9-3.0 mm long and 0.3-0.5 mm 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 C 16 : 0 , summed feature 3 (C 16 : 1 v7c and/or C 16 : 1 v6c) and summed feature 9 (iso-C 17 : 1 v9c and/or 10-methyl C 16 : 0 ). Phylogenetic analysis based on 16S rRNA gene sequences indicated that the closest cultivated relative of strain skN76 T was Acidiferrobacter thiooxydans m-1 T , with sequence similarity of 93 %. On the basis of its phylogenetic and phenotypic properties, strain skN76 T (5DSM 100313 T 5 NBRC 110942 T ) 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.

Sulfuricaulis limicola gen. nov., sp. nov., a sulfur oxidizer isolated from a lake

“…Acidiferrobacter thiooxydans is an acidophilic, iron oxidizer that requires an osmotic potential for growth (Hallberg et al, 2011). Sulfurifustis variabilis is a neutrophilic, sulfur oxidizer characterized by variable morphology (Kojima et al, 2015). In the present study, a novel autotrophic sulfur oxidizer related to these bacteria was isolated and characterized.…”

“…nov. The type strain of the type species is HA5 T (5DSM 100373The family Acidiferrobacteraceae in the order Acidiferrobacterales was recently established to accommodate two monospecies genera of chemolithoautotrophs, Acidiferrobacter and Sulfurifustis (Kojima et al, 2015). Acidiferrobacter thiooxydans is an acidophilic, iron oxidizer that requires an osmotic potential for growth (Hallberg et al, 2011).…”

Thermithiobacillus plumbiphilus sp. nov., a sulfur-oxidizing bacterium isolated from lead sulfide

“…For characterization of strain wk12 T , the isolate was cultured in bicarbonate-buffered low-salt defined medium unless otherwise specified (Kojima et al, 2015). The medium was composed as follows (l 21 ): 0.2 g MgCl 2 .…”

“…To assess the effect of NaCl concentration on growth, the isolate was inoculated into media supplemented with varying concentrations of NaCl (0, 3.33, 6.67, 13.3, 26.7, 66.7, 107, 133, 160, 170, 180, 187, 206, 227, 249, 274, 301, 340, 374, 411, 453, 498, 548 and 602 mM). The effect of pH on growth was tested in the same manner as described previously (Kojima et al, 2015). The buffering reagents (20 mM) and tested pH were as follows: sodium acetate buffer for pH 4.6, 4.7, 4.9, 5.6 and 5.9; MES for pH 5.8, 5.9, 6.1 and 6.3; PIPES for pH 6.3, 6.5 and 6.7; MOPS for pH 6.5 and 6.8; Tricine for pH 6.9, 7.1 and 7.2; and CHES for pH 6.5, 6.8, 7.1, 7.7, 8.6, 8.7, 9.2, 9.5, 9.7, and 9.8.…”

Sulfuriflexus mobilis gen. nov., sp. nov., a sulfur-oxidizing bacterium isolated from a brackish lake sediment

“…T was tested with a previously described method (Kojima et al, 2015), with a modification for the NaCl-requiring strain. The test was performed with media containing 2.0 % (w/v) NaCl, and the tested pH and buffering reagents were as follows: pH 5.9, 6.3, 6.4, 6.5, 6.8 and 7.2 with MES; pH 6.9, 7.0, 7.2, 7.3, 7.4 and 7.6 with PIPES; pH 7.7, 7.8, 7.9 and 8.2 with MOPS; pH 8.…”