Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field
A novel thermophilic bacterium, strain KW1T, was isolated from a coastal hydrothermal field on the Satsuma Peninsula, Kagoshima Prefecture, Japan. The variably Gram-stained cells were motile rods with flagella, did not form spores and proliferated at 52–78 °C (optimum, 70 °C), pH 5–8 (optimum, pH 7) and 0–4.5 % NaCl (optimum, 1.0 %). The novel isolate was a strictly aerobic heterotroph that utilized complex proteinaceous substrates as well as a variety of carboxylic acids and amino acids. The G+C content of the genomic DNA was 70.8 mol%. Analysis of 16S rRNA gene sequences indicated that strain KW1T is closely related to Thermaerobacter subterraneus C21T (98.4 % sequence similarity). However, the DNA–DNA hybridization value for strain KW1T and T. subterraneus ATCC BAA-137T was below 46 %. On the basis of the molecular and physiological traits of strain KW1T, it represents a novel species of the genus Thermaerobacter, for which the name Thermaerobacter litoralis sp. nov. is proposed. The type strain is KW1T (=JCM 13210T=DSM 17372T).