Roseomonas aerofrigidensis sp. nov., isolated from an air conditioner.

A Gram-stain-negative, strictly aerobic bacterium, designated HC1T, was isolated from an air conditioner in South Korea. Cells were orange, non-motile cocci with oxidase- and catalase-positive activities and did not contain bacteriochlorophyll a. Growth of strain HC1T was observed at 10-45 °C (optimum, 30 °C), pH 4.5-9.5 (optimum, pH 7.0) and 0-3 % (w/v) NaCl (optimum, 0 %). Strain HC1T contained summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0 and cyclo-C19 : 0ω8c as the major fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unknown aminolipid were detected as the major polar lipids. The major carotenoid was hydroxyspirilloxanthin. The G+C content of the genomic DNA was 70.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain HC1T formed a phylogenetic lineage within the genus Roseomonas. Strain HC1T was most closely related to the type strains of Roseomonas oryzae, Roseomonas rubra, Roseomonas aestuarii and Roseomonas rhizosphaerae with 98.1, 97.9, 97.6 and 96.8 % 16S rRNA gene sequence similarities, respectively, but the DNA-DNA relatedness values between strain HC1T and closely related type strains were less than 70 %. Based on phenotypic, chemotaxonomic and molecular properties, strain HC1T represents a novel species of the genus Roseomonas, for which the name Roseomonas aerofrigidensis sp. nov. is proposed. The type strain is HC1T (=KACC 19097T=JCM 31878T).