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

Abstract

A Gram-stain-negative, facultative anaerobic, non-motile, short-clavate and non-flagellated marine bacterium strain, designated JC075^T, was isolated from the Yongle Blue Hole in the South China Sea. Based on the 16S rRNA gene sequence, strain JC075^T was found to be closely related to Marinifilum albidiflavum FB208^T (97.10 %), Marinifilum flexuosum DSM 21950^T (96.43 %) and Marinifilum fragile JCM 15579^T (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^T 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^T was 35.8 mol%. On the basis of polyphasic analysis, strain JC075^T 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^T (=KCTC 15646^T=MCCC 1K03477^T=JCM 32401^T).