Ochrobactrum chromiisoli sp. nov., Isolated from Chromium-Contaminated Soil

Abstract

A Gram-stain-negative, non-spore-forming, flagellated, motile, aerobic, rod-shaped bacteria strain, designated YY2X^T, was isolated from chromium-contaminated soil. Phylogenetic analysis based on 16S rRNA gene, recA gene, and whole genome indicated that the strain represented a new member of the genus Ochrobactrum, family Brucellaceae, class Alphaproteobacteria. The phylogenetic trees based on 16 s rRNA gene, revealed that Falsochrobactrum ovis DSM26720^T (96.7%), Ochrobactrum gallinifaecis DSM15295^T (96.2%), and Pseudochrobactrum asaccharolyticum DSM25619^T (96.2%) are the most closely related phylogenetic neighbors of strain YY2X^T. The draft genome of YY2X^T was approximately 4,650,646 bp in size with a G + C content of 53.0 mol%. Average nucleotide identity and digital DNA-DNA hybridization values among strain YY2X^T and the selected Brucellaceae species were 71.4-83.1% and 13.5-42.7%, which are below the recommended cut-off values for species delineation. Growth of strain YY2X^T occurred within pH 5-10 (optimum, pH 7-8), 4 ℃-42 °C (optimum, 30 °C), and NaCl concentrations of 0.0-6.0% (optimum, 1.0%). Major quinone system was ubiquinone 10, the major fatty acids were C_16:0, C_18:1ω7c, and C_16:1ω7c and the major polyamines were spermidine and putrescine. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, and four undefined lipids. On the basis of the phenotypic, genotypic and chemotaxonomic traits, strain YY2X^T was considered to represent a novel species of the genus Ochrobactrum, for which the name Ochrobactrum chromiisoli sp. nov. is proposed. The type strain is YY2X^T (= CCTCC AB 2023035^T = JCM 36000^T).