Roseovarius azorensis sp. nov., isolated from seawater at Espalamaca, Azores

Abstract

A Gram-negative, motile, non-spore forming, rod shaped aerobic bacterium, designated strain SSW084^T, was isolated from a surface seawater sample collected at Espalamaca (38°33`N; 28°39`W), Azores. Growth was found to occur from 15 to 40 °C (optimum 30 °C), at pH 7.0–9.0 (optimum pH 7.0) and with 25–100 % seawater or 0.5–7.0 % NaCl in the presence of Mg2⁺ and Ca2⁺; no growth was found with NaCl alone. Colonies on seawater nutrient agar were observed to be punctiform, white, convex, circular, smooth, and translucent. Strain SSW084^T did not grow on Zobell marine agar and tryptic soy agar even when seawater supplemented. The major respiratory quinone was found to be Q-10 and the G + C content was determined to be 61.9 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SSW084^T belongs to the genus Roseovarius and that its closest neighbours are Roseovarius tolerans EL-172^T), Roseovarius mucosus DFL-24^T and Roseovarius lutimaris 112^T with 95.7, 95.4 and 95.3 % sequence similarity respectively. The remaining species of Roseovarius showed <95 % similarity. The polar lipids of strain SSW084^T were determined to be phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, an unidentified lipid and one unidentified aminolipid. The major fatty acids identified were identified as C_18:1 ω7c (52.5 %) and C_16:0 (13.8 %). On the basis of phenotypic, molecular and chemotaxonomic characteristics, strain SSW084^T is considered to represent a novel species of the genus Roseovarius, for which Roseovarius azorensis sp. nov is proposed. The type strain is SSW084^T (=KCTC 32421^T = MTCC 11812^T)