FIG. 4.

Phylogenetic tree based on 16S rRNA sequences showing the relationship between strain SB164P1 and its closest relatives as well as 62 other reference organisms of the delta subclass of the Proteobacteria. The triangles indicate groups of phylogenetically related species or genera: 1, Desulfobacter spp. plus Desulfobacterium, Desulfobacula, and Desulfosarcina spp.; 2, Syntrophobacter spp. plus Desulfoacinum and Desulforhabdus spp.; 3, Geobacter spp. plus Desulfuromonas, Desulfuromusa, and Pelobacter spp.; 4, Desulfovibrio spp. plus Desulfohalobium and Desulfomicrobium spp. The 16S rRNA sequence of E. coli was used as an outgroup reference. The scale bar represents the estimated number of base changes per nucleotide sequence position.