Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field

A novel thermophilic bacterium, strain KW1^T, 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 1 6S rRNA gene sequences indicated that strain KW1^T is closely related to Thermaerobacter subterraneus C21^T (98.4% sequence similarity). However, the DNA-DNA hybridization value for strain KW1^T and T subterraneus ATCC BAA-137^T was below 46%. On the basis of the molecular and physiological traits of strain KW1^T, it represents a novel species of the genus Thermaerobacter, for which the name Thermaerobacter litoralis sp. nov. is proposed. The type strain is KW1^T (=JCM 1321O^T = DSM 17372^T).