Marinifilum breve sp. nov., a marine bacterium isolated from the Yongle Blue Hole in the South China Sea and emended description of the genus Marinifilum.

A Gram-stain-negative, facultative anaerobic, non-motile, short-clavate and non-flagellated marine bacterium strain, designated JC075, was isolated from the Yongle Blue Hole in the South China Sea. Based on the 16S rRNA gene sequence, strain JC075 was found to be closely related to Marinifilum albidiflavum FB208 (97.10 %), Marinifilum flexuosum DSM 21950 (96.43 %) and Marinifilum fragile JCM 15579 (95.58 %), with less than 90.24 % sequence similarity to other genera of the family Marinifilaceae. The growth temperature was in the range of 10-37 °C, and the optimum temperature was 16 °C. Optimal growth occurred at pH 7.0 and in the presence of 3 % (w/v) NaCl. The isoprenoid quinone of strain JC075 was identified as menaquinone-7 and the predominant fatty acids (>10 %) were iso-C15 : 0 (47.9 %), summed feature 9 (C17 : 1 or/and iso-C17 : 1ω9c; 18.7 %) and iso-C17 : 0 3-OH (14.9 %). The major polar lipids were one phosphatidylethanolamine, one phospholipid, one aminophospholipid, one glycolipid, one aminolipid and two unidentified lipids. The DNA G+C content of strain JC075 was 35.8 mol%. On the basis of polyphasic analysis, strain JC075 was considered to represent a novel species of the genus Marinifilum, for which the name Marinifilumbreve sp. nov. is proposed. The type strain is JC075 (=KCTC 15646=MCCC 1K03477=JCM 32401).