Neptunomonas qingdaonensis sp. nov., isolated from intertidal sand.

A Gram-negative, motile, aerobic, oxidase- and catalase-positive rod, designated P10-2-4(T), was isolated from an intertidal sand sample collected from a coastal area of Qingdao (Yellow Sea), China. The isolate reduced nitrate to nitrite and grew at 4-33 °C and with 0.5-12 % (w/v) NaCl. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C18 : 1ω7c and C16 : 0. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The major respiratory quinone was Q-8. The genomic DNA G+C content was 45.1 %. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain P10-2-4(T) belonged to the genus Neptunomonas. The isolate shared the highest 16S rRNA gene sequence similarity (98.1 %) with Neptunomonas japonica JAMM 0745(T) and 96.9, 96.5 and 95.9 % sequence similarities with N. antarctica S3-22(T), N. concharum LHW37(T) and N. naphthovorans NAG-2N-126(T), respectively, strains of the other three recognized species in the genus. DNA-DNA relatedness between strain P10-2-4(T) and N. japonica JCM 14595(T) was 35.6 %. Furthermore, strain P10-2-4(T) could be distinguished from the representatives of the genus Neptunomonas by a combination of phenotypic characteristics, such as temperature and NaCl concentration for growth, nitrate reduction, DNase activity and assimilation of substrates. The data from this study suggests that strain P10-2-4(T) represents a novel species in the genus Neptunomonas, for which the name Neptunomonas qingdaonensis sp. nov. is proposed. The type strain is P10-2-4(T) ( = CGMCC 1.10971(T)  = KCTC 23686(T)).