Ochrobactrum rhizosphaerae sp. nov. and Ochrobactrum thiophenivorans sp. nov., isolated from the environment

Abstract

Two Gram-negative, rod-shaped, non-spore-forming bacteria, PR17(T) and DSM 7216(T), isolated from the potato rhizosphere and an industrial environment, respectively, were studied for their taxonomic allocation. By rrs (16S rRNA) gene sequencing, these strains were shown to belong to the Alphaproteobacteria, most closely related to Ochrobactrum pseudogrignonense (98.4 and 99.3 % similarity to the type strain, respectively). Chemotaxonomic data (major ubiquinone Q-10; major polyamines spermidine, sym-homospermidine and putrescine; major polar lipids phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and phosphatidylcholine and the Ochrobactrum-specific unidentified aminolipid AL2; major fatty acids C(18 : 1)omega7c and C(19 : 0) cyclo omega8c) supported the genus affiliation. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of the isolates from all hitherto-described Ochrobactrum species. Hence, both isolates represent novel species of the genus Ochrobactrum, for which the names Ochrobactrum rhizosphaerae sp. nov. (type strain PR17(T) =CCUG 55411(T) =CCM 7493(T) =DSM 19824(T)) and Ochrobactrum thiophenivorans sp. nov. (type strain DSM 7216(T) =CCUG 55412(T) =CCM 7492(T)) are proposed.