Pseudophaeobacter profundi sp. nov., isolated from the Western Pacific Ocean

A novel Gram-stain-negative, facultatively anaerobic and heterotrophic bacterium, designated strain ZH257^T, was isolated from in situ enrichment samples incubated on the seamount floor of the Western Pacific Ocean. Cells were rod-shaped, oxidase- and catalase- positive, and motile by means of polar flagella. Strain ZH257^T grew at 4-37 °C (optimum, 28-32 °C), pH 6.0-9.0 (optimum, pH 7.0) and with 2.0-9.0 % (w/v) NaCl (optimum, 3.0-4.0 %). Strain ZH257^T was most closely related to members of the genus Pseudophaeobacter, sharing 99.13, 98.27 and 96.89 % 16S rRNA gene sequence identities with Pseudophaeobacter flagellatus GDMCC 1.2988^T, Pseudophaeobacter arcticus DSM 23566^T and Pseudophaeobacter leonis DSM 25627^T, respectively. The DNA G+C content was 59.2 mol%. The estimated average nucleotide identity and digital DNA-DNA hybridization values between strain ZH257^T and its closely related species were 79.61-93.04 % and 23.10-50.20 %, respectively. Strain ZH257^T harboured complete denitrification and nitrate assimilation pathways. Strain ZH257^T contained summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c) as major fatty acids (>5 %), and Q-10 as the major respiratory quinone. The polar lipid profile contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, an unidentified phospholipid, an unidentified aminolipid and four unidentified lipids. The combined phenotypic, genotypic and chemotaxonomic data showed that strain ZH257^T represents a novel species of the genus Pseudophaeobacter, for which the name Pseudophaeobacter profundi sp. nov. is proposed, with the type strain ZH257^T (=MCCC M29024^T=KACC 23147^T).