Arthrobacter defluvii sp. nov., 4-chlorophenol-degrading bacteria isolated from sewage.

Two 4-chlorophenol-degrading bacteria, strains 4C1-aT and 4C1-b, were isolated from sewage flowing into Geumho River near the Daegu industrial complex in Korea. Cells of the strains were Gram-positive and non-motile, displayed a rod-coccus life cycle and formed creamy white colonies on R2A agar or peptone-carbohydrate agar. The strains had chemotaxonomic markers that were consistent with classification in the genus Arthrobacter, i.e. MK-9(H2) as the major menaquinone, iso- and anteiso-branched components as the predominant fatty acids, galactose, glucose and rhamnose as cell-wall sugars, peptidoglycan-type A3alpha, and DNA G+C content of 63.5-64.4 mol%. Phylogenetic analysis, based on 16S rRNA gene sequencing, showed that the strains were most similar to Arthrobacter chlorophenolicus DSM 12829T, Arthrobacter oxydans DSM 20119T and Arthrobacter scleromae JCM 12642T (with 98.4, 97.8 and 97.8 % similarity, respectively) and formed a separate lineage with A. chlorophenolicus in the genus Arthrobacter. Combined phenotypic data and DNA-DNA hybridization data supported the conclusion that strains 4C1-aT and 4C1-b represent a novel species in the genus Arthrobacter, for which the name Arthrobacter defluvii sp. nov. is proposed. The type strain is 4C1-aT (=KCTC 19209T=DSM 18782T).