Fontibacter flavus gen. nov., sp. nov., a member of the family 'Cyclobacteriaceae', isolated from a hot spring

The taxonomic position of a bright orange-pigmented bacterial strain, designated CC-GZM-130(T), isolated from a water sample of the Guan-zing-ling hot spring, southern Taiwan, was studied. The strain was able to grow on nutrient agar at 25-40 degrees C and in the presence of 1-3% (w/v) NaCl. Comparative analyses of the 16S rRNA gene sequence showed that the isolate was grouped in the vicinity of the genus Aquiflexum with the highest sequence similarity of 92.1% to the type strain of Aquiflexum balticum, followed by sequence similarities of 92.0, 91.6 and 91.5% to the type strains of Algoriphagus ornithinivorans, Algoriphagus hitonicola and Belliella baltica, respectively. The polyamine pattern showed that the major compound was sym-homospermidine. The quinone system was menaquinone MK-7. The polar lipid profile was composed predominantly of phosphatidylethanolamine, three polar lipids and one aminolipid. Minor amounts of other lipids were also detectable. The main characteristics of the fatty acid profiles of strain CC-GZM-130(T), B. baltica and Aquiflexum balticum were similar, with iso-C(15:0), iso-C(17:1)omega 9c and iso-C(17:0)3-OH as the major fatty acids, but some qualitative and quantitative differences were observed. The DNA G + C content of the novel strain was 53.2 mol%. The isolate clearly differed genotypically and phenotypically from representatives of the most closely related genera. On the basis of these differences, a novel species in a new genus, Fontibacter flavus gen. nov., sp. nov., is proposed with CC-GZM-130(T) (=CCUG 57694(T)=CCM 7650(T)) as the type strain of the type species.