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 ZSDE20T, was isolated from the surface seawater of Qingdao offshore. Phylogenetic analysis of the 16S rRNA gene of strain ZSDE20T, affiliated it to the genus Photobacterium. It was closely related to Photobacterium lutimaris DF-42T (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 ZSDE20T 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 ZSDE20T was 45.6mol%. Average nucleotide identity (ANI) values between ZSDE20T and its reference species were lower than the threshold for species delineation (95-96%); in silico DNA-DNA hybridization further showed that strain ZSDE20T had less than 70% similarity to its relatives. Based on the polyphasic evidences, strain ZSDE20T 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 ZSDE20T (= MCCC 1K06283T = KCTC 82885T).