Photobacterium alginatilyticum sp. nov., a marine bacterium isolated from bottom seawater.

A Gram-straining-negative, facultatively aerobic, rod-shaped strain, motile by a polar flagellum and designated P03D4T, was isolated from the bottom seawater of the East China Sea. Growth occurred at 10-50 °C (optimum 32 °C), pH 5.0-10.0 (optimum pH 6.0) and in the presence of 1-7 % (w/v) NaCl (optimum 3 %). Phylogenetic analysis based on 16S rRNA gene sequence placed P03D4T within the genus Photobacterium of the family Vibrionaceae in the class Gammaproteobacteria, and revealed that strain P03D4T was most closely related to Photobacterium frigidiphilum SL13T with 96.9 % sequence similarity and had sequence similarities with other species of the genus Photobacterium in the range 94.6-96.9 %. The dominant fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C16 : 0. The polar lipids of strain P03D4T comprised phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and one unknown lipid. The major respiratory quinone was ubiquinone-8 (Q-8). The DNA G+C content of strain P03D4T was 44.3 mol%. On the basis of the evidence from this polyphasic study, strain P03D4T is proposed as representing a novel species of the genus Photobacterium, for which the name Photobacterium alginatilyticum sp. nov. is proposed. The type strain is P03D4T (=KCTC 52365T=MCCC 1K03200T=CGMCC 1.15764T).