Dokdonella immobilis sp. nov., isolated from a batch reactor for the treatment of triphenylmethane dye effluent.

A Gram-staining-negative, non-endospore-forming, non-flagellated, non-motile and rod-shaped bacterium, designated strain LM2-5(T), was isolated from activated sludge in a sequencing batch reactor used for the treatment of triphenylmethane dye effluent. The taxonomy of strain LM2-5(T) was studied by phenotypic, chemotaxonomic and phylogenetic methods. Strain LM2-5(T) was aerobic, heterotrophic and positive for oxidase but negative for catalase activity. It grew at 16-37 °C (optimum 25 °C) and at pH 5.0-8.5 (optimum between pH 6.5 and pH 7.0). NaCl was not obligatory for growth but was tolerated at concentrations up to 2.0 % (w/v) NaCl. The novel strain formed yellow colonies on trypticase soy agar. Cells of strain LM2-5(T) were rods that measured 0.3-0.5 µm in width and 3.0-5.0 µm in length. The predominant respiratory quinone was Q-8. The major fatty acids were iso-C15 : 0 and iso-C17 : 1ω9c. The genomic DNA G+C content was 66.7 mol%. In phylogenetic analyses based on 16S rRNA gene sequences, strain LM2-5(T) clustered with members of the genus Dokdonella and appeared most closely related to Dokdonella koreensis DS-123(T) (96.4 % sequence similarity), Dokdonella fugitiva A3(T) (96.1 %), Dokdonella soli KIS28-6(T) (95.7 %) and Dokdonella ginsengisoli Gsoil 191(T) (95.7 %). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain LM2-5(T) was considered to represent a novel species of the genus Dokdonella, for which the name Dokdonella immobilis is proposed. The type strain is LM2-5(T) ( = CGMCC 1.7659(T)  = JCM 15763(T)).