Tepidimonas fonticaldi sp nov., a slightly thermophilic betaproteobacterium isolated from a hot spring

A slightly thermophilic bacterial strain, designated AT-A2(T), was isolated from a hot spring water sample taken from the Antun hot spring in Taiwan and characterized using a polyphasic taxonomic approach. Cells of strain AT-A2(T) were aerobic, Gram-negative, motile by a single polar flagellum and formed non-pigmented colonies. Growth occurred at 35-60 degrees C (optimum, 55 degrees C), with 0 1.0 % NaCl (optimum, 0.2%) and at pH 7.0-9.0 (optimum, pH 7.0). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain AT-A2(T) belonged to the genus Tepidimonas and its closest neighbour was Tepidimonas thermarum AA-1(T) with a sequence similarity of 97.5%. The predominant cellular fatty acids were C-16:0 (40.2 %), summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c; 20.1 %) and C-17:0 cyclo (11.5 %). The major respiratory quinone was Q-8. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an uncharacterized aminolipid and several uncharacterized phospholipids. The DNA G+C content of strain AT-A2(T) was 70.1 mol%. The mean level of DNA DNA relatedness between strain AT-A2(T) and Tepidimonas thermarum AA-1(T) was 23.9%. On the basis of the phylogenetic and phenotypic data, strain AT-A2(T) should be classified as representing a novel species, for which the name Tepidimonas fonticaldi sp. nov. is proposed. The type strain is AT-A2(T) (=LMG 26746(T)=KCTC 23862(T)=BCRC 80391(T)).