Aureimonas ferruginea sp. nov. and Aureimonas rubiginis sp. nov., two siderophore-producing bacteria isolated from rusty iron plates.

Two novel siderophore-producing strains designated CC-CFT023(T) and CC-CFT034(T), isolated from a rusty iron plate, are characterized in this study. Cells of both strains were catalase- and oxidase-positive. Strain CC-CFT023(T) showed a high pairwise 16S rRNA gene sequence similarity to Aureimonas altamirensis LMG 23375(T) (96.0 %), whereas, strain CC-CFT034(T) shared a maximum similarity to Aureimonas ureilytica DSM 18598(T) (95.8 %). The predominant quinone system was ubiquinone (Q-10) and the DNA G+C contents of CC-CFT023(T) and CC-CFT034(T) were 69.5 mol% and 67.7 mol%, respectively. The major fatty acids of these strains were C16 : 0, C18 : 0, C19 : 0 cyclo ω8c, C18 : 1 2-OH and summed features 3 and 8, consisting of C16 : 1ω7c/C16 : 1ω6c and C18 : 1ω7c/C18 : 1ω6c, respectively. Polar lipid profiles of both of these isolates include diphosphatidylglycerol (DPG), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and most importantly sulfoquinovosyldiacylglycerol (SQDG), which is one of the typical molecular features reported to delineate the members of the genus Aureimonas from their closest relatives, species of the genus Aurantimonas. Based on the phylogenetic, phenotypic and chemotaxonomic features, strains CC-CFT023(T) and CC-CFT034(T) represent two novel species within the genus Aureimonas, for which the names Aureimonas ferruginea sp. nov. (type strain CC-CFT023(T) = BCRC 80439(T) = JCM 18444(T)) and Aureimonas rubiginis sp. nov. (type strain CC-CFT034(T) = BCRC 80440(T) = JCM 18445(T)) are proposed.