Photobacterium pectinilyticum sp. nov., a novel bacterium isolated from surface seawater of Qingdao offshore.

Abstract

A Gram-staining-negative, facultative aerobic, motile strain, designated strain ZSDE20^T, was isolated from the surface seawater of Qingdao offshore. Phylogenetic analysis of the 16S rRNA gene of strain ZSDE20^T, affiliated it to the genus Photobacterium. It was closely related to Photobacterium lutimaris DF-42 ^T (98.92% 16S rRNA gene sequence similarity). Growth occurred at 4-28ºC (optimum 28ºC), pH 1.0-7.0 (optimum 7.0) and in the presence of 1-7% (w/v) NaCl (optimum 3%). The dominant fatty acids were summed feature 3 (C16:1 ω7c or/and C16:1 ω6c, 34.23%), summed feature 8 (C18:1 ω7c and C18:1 ω6c, 10.36%) and C16:0 (20.05%). The polar lipids of strain ZSDE20^T comprised phosphatidylethanolamine, phosphatidylcholine, lyso-phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol dimannoside, phosphatidylinositol mannosides and two unknown lipids. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G + C content of strain ZSDE20^T was 45.6 mol%. Average nucleotide identity (ANI) values between ZSDE20^T and its reference species were lower than the threshold for species delineation (95-96%); in silico DNA-DNA hybridization further showed that strain ZSDE20^T had less than 70% similarity to its relatives. Based on the polyphasic evidences, strain ZSDE20^T is proposed as representing a novel species of the genus Photobacterium, for which the name Photobacterium pectinilyticum sp. nov. is proposed. The type strain is ZSDE20^T (= MCCC 1K06283^T = KCTC 82885 ^T).