Phylogenetic relationships among members of the Comamonadaceae, and description of Delftia acidovorans (den Dooren de Jong 1926 and Tamaoka et al. 1987) gen. nov., comb. nov.

The phylogenetic relationships among members of the family Comamonadaceae a nd several unclassified strains were studied by direct sequencing of their PCR-amplified 16S rRNA genes. Based on the 16S rRNA gene sequence analysis, members of the family formed a coherent group. The closest relatives are s pecies of the Rubrivivax sub-group: Leptothrix discophora, Ideonella dechlo ratans and Rubrivivax gelatinosus. The genus Hydrogenophaga formed two subc lusters, as did the species of Acidovorax, whereas the five species of the genus [Aquaspirillum] were polyphyletic. Comamonas acidovorans was phylogen etically distant from the type species of Comamonas, Comamonas terrigena. O n the basis of this work and previous studies, Comamonas acidovorans is rem oved from the genus Comamonas and renamed as Delftia acidovorans gen. nov., comb, nov. Descriptions of the new genus Delftia and of the type species D elftia acidovorans, for which the type strain is ATCC 15668(T), are present ed.