Cereibacter flavus sp. nov., a novel member of the family Rhodobacteraceae isolated from seawater of the South China Sea and reclassification of Rhodobacter alkalitolerans as Cereibacter alkalitolerans comb. nov.

A Gram-stain-negative, aerobic, motile, ovoid-shaped and yellow-coloured strain, designated SYSU M79828 ^T , was isolated from seawater collected from the South China Sea. Growth of this strain was observed at 4-37 °C (optimum, 28 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-6% NaCl (optimum, 3.0 %, w/v). The respiratory quinone was found to be Q-10. Major fatty acid constituents were C _18 : 1  ω 7 c /C _18 : 1  ω 6 c , C _18 : 1 ω 7 c 11-methyl and C _18 : 0 (>5 % of total). The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphoglycolipid, two unidentified phospholipid, one unidentified lipid and an unidentified glycolipid. The genomic DNA G+C content was 64.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M79828 ^T belonged to the genus Cereibacter and had the highest sequences similarity to ' Rhodobacter xinxiangensis ' TJ48 ^T (98.41 %). Based on 16S rRNA gene phylogeny, physiological and chemotaxonomic characterizations, we consider that strain SYSU M79828 ^T represents a novel species of the genus Cereibacter , for which the name Cereibacter flavus sp. nov. is proposed. The type strain is SYSU M79828 ^T (=GDMCC 1.3803 ^T =KCTC 92893 ^T ). In addition, according to the results of phylogenetic analysis and similar taxonomic characteristics, we propose that Rhodobacter alkalitolerans should be reclassified as Cereibacter alkalitolerans comb. nov.