TAXONOMIC POSITION OF AROMATIC-DEGRADING DENITRIFYING PSEUDOMONAD STRAINS K-172 AND KB-740 AND THEIR DESCRIPTION AS NEW MEMBERS OF THE GENERA THAUERA, AS THAUERA-AROMATICA SP-NOV, AND AZOARCUS, AS AZOARCUS-EVANSII SP-NOV, RESPECTIVELY, MEMBERS OF THE BETA-SUBCLASS OF THE PROTEOBACTERIA

In the past workers have isolated several pseudomonad strains which ha ve been used for studies of anaerobic aromatic metabolism. The best st udied of these strains are strains KB 740(T) (T = type strain) and K 1 72(T). The taxonomic positions of these two organisms were determined by classical methods, including experiments to determine substrate spe ctrum, quinone type, and total fatty acid composition. Our results cle arly excluded these strains from the authentic genus Pseudomonas, whic h belongs to the gamma subclass of the Proteobacteria. Instead, the pr operties of these organisms indicated that they belong to the beta sub class of the Proteobacteria. The sequences of the 16S ribosomal DNA ge nes confirmed this conclusion and indicated that strain K 172(T) repre sents a new species of the genus Thauera, Thauera aromatica, and that strain KB 740(T) represents a new species of the genus Azoarcus, Azoar cus evansii.