Tenacibaculum holothuriorum sp. nov., isolated from the sea cucumber Apostichopus japonicus intestine.

A novel bacterial strain, designated S2-2T, was isolated from the intestine of a sea cucumber Apostichopus japonicus in Xiapu, Fujian province, China. Strain S2-2T was found to be aerobic, Gram-stain-negative, pale yellow, rod-shaped, oxidase- and catalase-positive. Growth occurred at 15-36 °C (optimum, 25-32 °C), in the presence of 2-7% sea salt (w/v, optimum, 3-5%) and at pH 6-9 (optimum, pH 7.0). The isolate was able to hydrolyse gelatin, casein and DNA, but unable to degrade Tween 20, 40 and 80, starch and cellulose. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S2-2T represented a member of the genus Tenacibaculum, with highest sequence similarity to Tenacibaculum aiptasiae a4T (96.9% similarity), followed by Tenacibaculum xiamenense WJ-1T (96.5% similarity) and showed lower similarities (93.3-95.9%) with other members of the genus Tenacibaculum. The major cellular fatty acids were summed feature 3 (comprising C16 : 1ω6c/C16 : 1ω7c, 33.8%), iso-C15 : 0 (13.7%), iso-C15 : 1G (8.6%), iso-C15 : 0 3-OH (5.3%) and C15 : 0 3-OH (5.1%). The DNA G+C content of the chromosomal DNA was determined to be 31.8 mol%. The respiratory quinone was determined to be MK-6. Phosphatidylethanolamine, phosphatidylglycerol, one unknown aminophospholipid, one unknown phospholipid, one unknown glycolipid and five unknown lipids were detected as major polar lipids. Hence, the combined genotypic and phenotypic data indicated that strain S2-2T represents a novel species of the genus Tenacibaculum, for which the name Tenacibaculum holothuriorum sp. nov. is proposed. The type strain is S2-2T ( = MCCC 1A09872T = LMG 27758T).