Albidovulum molybdatiresistens sp. nov., a molybdate-resistant bacterium isolated from river water

A Gram-stain-negative, aerobic, non-motile, catalase- and oxidase-positive, white rod-shaped strain, RF13^T, was isolated from water samples of the Qingliang River in Fucheng County, Hebei Province, China, and was grown at 15-42 °C (optimum 35 °C), pH 6.0-8.0 (optimum pH 7), and 0-0.5% (w/v) NaCl (optimum concentration 0%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RF13^T belonged to the genus Albidovulum, with closest sequence similarity to Albidovulum salinarum MCCC 1K0602^T (97.2%), Frigidibacter oleivorans CGMCC 1.3778^T (97.2%), Allgaiera indica MCCC 1A01802^T (96.8%), and Pseudothioclava arenosa KCTC 52190^T (96.4%). The genome size of strain RF13^T was 3.7 Mb, and the DNA G+C content was 64.6%. The DNA-DNA hybridisation value (dDDH), average nucleotide identity (ANI), and average amino acid identity (AAI) between strain RF13^T and the reference strain were less than 20.0%, 78.8%, and 72.8%, respectively. Chemotaxonomic analysis revealed Summed feature 8 (48.4%) (C_18:1 ω6c and/or C_18:1 ω7c), C_18:1 ω7c 11-methyl (22.1%), C_18:0 3OH (7.9%), and C_10:0 3OH (5.0%) as predominant fatty acids. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminolipids, two unidentified phospholipids, and three unidentified lipids. The predominant isoprenoid quinone was ubiquinone-10 (Q-10), and a small amount of Q-9 was also detected. In addition, strain RF13^T exhibited a minimum inhibitory concentration (MIC) of 20 mM for molybdate in R2A broth medium and was capable of reducing molybdate to molybdenum blue. Based on the results of biochemical, physiological, phylogenetic, and chemotaxonomic analyses, combined with 16S rRNA gene sequence analyses and draft genome sequence comparisons, strain RF13^T was considered to represent a novel species of the genus Albidovulum, and was therefore named Albidovulum molybdatiresistens sp. nov. The type strain was RF13^T (= GDMCC 1.3414^T= JCM 35643^T).