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

A novel sulfur-oxidizing bacterium, strain HA5T, was isolated from sediment of a lake in Japan. The cells were rod-shaped (0.3-0.5 × 1.2-6.0 μm) and Gram-stain-negative. The G+C content of the genomic DNA was 63 mol%. The major components in the cellular fatty acid profile were C16 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The strain oxidized thiosulfate, tetrathionate and elemental sulfur as electron donors to support autotrophic growth. Growth was observed at a temperature range of 8-37 °C, with optimum growth at 28-32 °C. The pH range for growth was pH 6.1-9.2. Optimum growth of the isolate was observed in medium without NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belongs to the family Acidiferrobacteraceae in the class Gammaproteobacteria. The closest relative was Sulfurifustis variabilis skN76T with the highest 16S rRNA gene sequence similarity of 93 %. On the basis of phylogenetic and phenotypic properties, strain HA5T is proposed to represent a novel species of a new genus, Sulfuricaulis limicola gen. nov., sp. nov. The type strain of the type species is HA5T ( = DSM 100373T = NBRC 110752T).