Phaeovulum Molybdatiresistens sp. nov., a Molybdate-resistant Bacterium Isolated from Eutrophic Pond Water

A Gram-stain-negative, aerobic, non-motile, catalase- and oxidase-positive, light brown, rod-shaped strain NW3^T, was isolated from a eutrophic pond located in Yifengdian town, Qingdao city, Shandong province, China. The strain grew at 28-42°C (optimum, 30°C), pH 6-10 (optimum, pH 7), and in the presence of 0.5-2.0% (w/v) NaCl (optimum, 1%). Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain NW3^T belongs to the genus Phaeovulum, and the closest members were Phaeovulum vinaykumarii JCM 14544^T and Defluviimonas salinarum MCCC 1K07180^T with 96.8% similarity, followed by Frigidibacter oleivorans CGMCC 1.13778^T (96.7%). The draft genome size of strain NW3^T was 3.61 Mbp, and the DNA G + C content was 65.4%. Digital DNA-DNA hybridization (≤ 21.1%), average nucleotide identity (≤ 78.0%), and average amino acid identity (≤ 74.3%) values between NW3^T and reference strains supported its status as a novel species. The major fatty acids (≥ 5.0%) were summed feature 8 (82.6%, C_18:1 ω6c and/or C_18:1 ω7c) and C_18:1 ω7c 11-methyl (8.0%), with Q-10 being the predominant isoprenoid quinone. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, five unidentified lipids, and an unidentified aminolipid. The genome of strain NW3^T contained a variety of putative molybdate resistant genes. Based on polyphasic taxonomic analyses, strain NW3^T is proposed as a novel species of the genus Phaeovulum, for which the name Phaeovulum molybdatiresistens sp. nov. is proposed. The type strain is NW3^T (= GDMCC 1.3054^T = JCM 35387^T).