Thermobacterium salinum gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from a hydrothermal zone

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterial strain, designated as strain TK19130 T , was isolated from the Lonqi hydrothermal zone in the Southwest Indian Ridge. Growth occurred with 1–12 % (w/v) NaCl (optimum, 2–4 %), at 10–40 °C (optimum, 30–35 °C) and at pH 6.0–9.0 (optimum, pH 7.0–8.0). The genome of strain TK19130 T was 3.15 Mb, with a DNA G+C content of 41.35 %. Based on the results of 16S rRNA gene sequence analysis, strain TK19130 T was affiliated with the family Flavobacteriaceae , in which the highest similarity was 90.54 % to Aureisphaera salina A6D-50 T , under the genus demarcation boundary (94.50 %). Average nucleotide identity values between strain TK19130 T and adjacent strains were 67.17–72.00 %, lower than the recommended threshold of 73.98 % for genus delineation. The predominant respiratory quinone of strain TK19130 T was menaquinone 6. Major polar lipids were phosphatidylethanolamine, three aminolipids and one unidentified polar lipid. Major fatty acids were detected as iso-C 15 : 1 G, iso-C 15 : 0 and iso-C 17 : 0 3-OH. Based on the polyphasic taxonomic evidence presented above, strain TK19130 T formed an independent branch representing a new species of a novel genus within the family Flavobacteriaceae , for which the name Thermobacterium salinum gen. nov., sp. nov. is proposed. The type strain is TK19130 T (=CGMCC 1.18993 T =JCM 35842 T =MCCC M28200 T ).