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 degrees C (optimum, 70 degrees 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 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 13210(T) = DSM 17372(T)).