Sulfuritalea hydrogenivorans gen. nov., sp. nov., a facultative autotroph isolated from a freshwater lake

Abstract

A novel facultatively autotrophic bacterium, designated strain sk43HT, was isolated from water of a freshwater lake in Japan. Cells of the isolate were curved rods, motile and Gram-reaction-negative. Strain sk43HT was facultatively anaerobic and autotrophic growth was observed only under anaerobic conditions. The isolate oxidized thiosulfate, elemental sulfur and hydrogen as sole energy sources for autotrophic growth and could utilize nitrate as an electron acceptor. Growth was observed at 8–32 °C (optimum 25 °C) and 6.4–7.6 (optimum pH 6.7–6.9). Optimum growth of the isolate occurred at NaCl concentrations of less than 50 mM. The G+C content of genomic DNA was around 67 mol%. The fatty acid profile of strain sk43HT when grown on acetate under aerobic conditions was characterized by the presence of C16 : 0 and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) as the major components. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain was a member of the class Betaproteobacteria showing highest sequence similarity with Georgfuchsia toluolica G5G6T (94.7 %) and Denitratisoma oestradiolicum AcBE2-1T (94.3 %). Phylogenetic analyses were also performed using genes involved in sulfur oxidation. On the basis of its phylogenetic and phenotypic properties, strain sk43HT ( = DSM 22779T  = NBRC 105852T) represents a novel species of a new genus, for which the name Sulfuritalea hydrogenivorans gen. nov., sp. nov. is proposed.