Sulfurisoma sediminicola gen. nov., sp nov., a facultative autotroph isolated from a freshwater lake

A novel facultatively autotrophic bacterium, strain BSN1(T) was isolated from sediment of a freshwater lake in Japan. The cells were rod-shaped, motile and Gram-stain-negative. As sole energy sources for autotrophic growth, the strain oxidized thiosulfate, elemental sulfur and hydrogen. Strain BSN1T was a facultative anaerobe utilizing nitrate as an electron acceptor. Growth was observed at temperatures lower than 34 C, and the optimum growth was observed at 30-32 degrees C. The range of pH for growth was pH 6.8-8.8, and the optimum pH was pH 7.8-8.1. The optimum growth of the isolate occurred at concentrations of NaCl less than 50 mM. The G+C content of genomic DNA was 67 mol%. The major component in the fatty acid profile of strain BSN1(T) grown on fumarate was summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH). Phylogenetic analysis based on 165 rRNA gene sequences indicated that the strain was a member of the class Betaproteobacteria, and it showed the highest sequence similarity with Georgfuchsia toluolica G5G6(T) (96.2%). Phylogenetic analyses were also performed on genes involved in sulfur oxidation. On the basis of its phylogenetic and phenotypic properties, strain BSN1(T) (= DSM 26916(T)=NBRC 109412(T)) is proposed as the type strain of a novel species of a novel genus, Sulfurisoma sediminicola gen. nov., sp. nov.