Description of Pseudaminobacter gen. nov. with two new species, Pseudaminobacter salicylatoxidans sp. nov. and Pseudaminobacter defluvii sp. nov.

An aerobic bacterium, strain BN12(T), which degrades substituted naphthalenesulfonates and substituted salicylates was isolated from a 6-aminonaphthalene-2-sulfonate-degrading microbial consortium originating from the River Elbe, Germany, Chemotaxonomic investigations of quinones, polyamines and polar lipids allowed allocation of this strain to the alpha-subclass of the Proteobacteria and revealed similarity to species of the genera Aminobacter, Chelatobacter and Mesorhirobium. This was confirmed by typing with 16S rRNA-targeted oligonucleotide probes and 16S rDNA sequencing and phylogenetic analysis, indicating that BN12(T) clusters most closely with a strain 'Thiobacillus' THI 051(T) and with the above genera but comprising a separate branch. DNA-DNA hybridizations demonstrated that strain BN12(T) is different from all species of Aminobacter currently described and recognized. The fatty acid patterns, substrate utilization profile and biochemical characteristics displayed no obvious similarity to the characteristics of Aminobacter and Chelatobacter species. 'Thiobacillus' THI 051(T), however, revealed phenotypic similarities to BN12(T). Furthermore, 16S rRNA sequences of Chelatobacter heintzii showed a high similarity to the 16S rRNA sequences of all currently recognized Aminobacter species. On the basis of these and previously published results, the new genus Pseudaminobacter is proposed, harbouring the two new species Pseudaminobacter salicylatoxidans sp, nov, and Pseudaminobacter defluvii sp. nov. The type strains are BN12(T) (= DSM 6986(T)) and THI 051(T) (= IFO 14570(T)), respectively.