Rhizobium borbori sp. nov., aniline-degrading bacteria isolated from activated sludge

Three aniline-degrading bacteria, strains DN316(T), DN316-1 and DN365, were isolated from activated sludge. According to 16S rRNA gene sequence-based phylogenetic analysis, the isolates belonged to the genus Rhizobium, with Rhizobium (=Agrobacterium) radiobacter LMG 140(T) as the closest relative, with 96.5% sequence similarity. Phylogenetic analysis of the representative strain DN316(T) using sequences of the glnA, thrC and recA genes and the 16S-23S intergenic spacer region confirmed the phylogenetic arrangement obtained from analysis of the 16S rRNA gene. DNA-DNA relatedness between DN316(T) and R. radiobacter LMG 140(T) was 43.7%, clearly indicating that the representative strain DN316(T) represents a novel species. Phenotypic and biochemical characterization of the isolates and insertion sequence-PCR fingerprinting patterns showed several distinctive features that differentiated them from closely related species. The major components of the cellular fatty acids were C(18:1)omega 7c (57.10%), C(16:0) (11.31%) and C(19:0) cyclo omega 8c (10.13%). Based on our taxonomic analysis, the three isolates from activated sludge represent a novel species of the genus Rhizobium, for which the name Rhizobium borbofi sp. nov. is proposed. The type strain is DN316(T) (=CICC 10378(T) =LMG 23925(T)).