Mizugakiibacter sediminis gen. nov., sp. nov., isolated from a freshwater lake.

A novel, moderately thermophilic, bacterial strain (skMP5(T)) was isolated from sediment of a freshwater lake in Japan. The cells were rod-shaped, motile and Gram-stain-negative. Growth was observed at temperatures ranging from 25 to 52 °C, with optimum growth observed at 48-50 °C. The pH range for growth was pH 5.0-8.2, with optimum growth at pH 6.0-7.0. The G+C content of genomic DNA was 72 mol%. The major components in the fatty acid profile were iso-C17 : 0 and iso-C17 : 1ω9c. The predominant isoprenoid quinone of the strain was ubiquinone Q-8. The strain was facultatively anaerobic, and reduced nitrate to nitrite under anoxic conditions. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate was a member of the family Xanthomonadaceae within the class Gammaproteobacteria, showing highest sequence similarity with Tahibacter aquaticus RaM5-2 (93.6 %) and Metallibacterium scheffleri DKE6(T) (93.3 %). On the basis of phylogenetic and phenotypic properties, strain skMP5(T) represents a novel species of a new genus, Mizugakiibacter sediminis gen. nov., sp. nov. The type strain of the type species is skMP5(T) ( = DSM 27098(T) = NBRC 109608(T)).