Phylogenetic and metabolic diversity of bacteria degrading aromatic compounds under denitrifying conditions, and description of Thauera phenylacetica sp. nov., Thauera aminoaromatica sp. nov., and Azoarcus buckelii sp. nov.

Abstract

Six strains of denitrifying bacteria isolated from various oxic and anoxic habitats on different monocyclic aromatic substrates were characterized by sequencing 16S rRNA genes, determining physiological and morphological traits, and DNA-DNA hybridization. According to these criteria, strains S100, SP and LG356 were identified as members of Thauera aromatica. Strains B5-1 and B5-2 were tentatively affiliated to the species Azoarcus tolulyticus. Strains B4P and S2 were only distantly related to each other and to other described Thauera species. These two strains are proposed as the type strains of two new species, Thauera phenylacetica sp. nov. and Thauera aminoaromaticasp. nov., respectively. By 16S rRNA gene analysis, strain U120 was highly related to the type strains of Azoarcus evansii and Azoarcus anaerobius, whereas corresponding DNA-DNA reassociation values indicated only a low degree of genomic relatedness. Based upon a low DNA similarity value and the presence of distinguishing physiological properties, strain U120 is proposed as the type strain of a new species, Azoarcus buckelii sp. nov. Almost all of the new isolates were obtained with different substrates. The highly varied substrate spectra of the isolates indicates that an even higher diversity of denitrifying bacteria degrading aromatic compounds would be discovered in the different habitats by using a larger spectrum of aromatic substrates for enrichment and isolation.

Tepidiphilus margaritifer gen. nov., sp. nov., isolated from a thermophilic aerobic digester

“…The 16S rDNA sequence of strain N2-214 T was not closely related to those of other genera within this subclass, the highest similarities (approx. 92-93 %) being to the sequences of Azoarcus buckelii (Mechichi et al, 2002), Thauera aromatica (Anders et al, 1995) and H. thermoluteolus (Hayashi et al, 1999). Comparative evolutionary distance analyses of the 16S rDNA sequence of strain N2-214 T demonstrated that it branched from the lineage leading to the genus Hydrogenophilus (Fig.…”

“…Phylogenetic analysis of the 16S rDNA sequence of strain N2-214 T showed its affiliation to the b-Proteobacteria, a result that is in agreement with the polar lipid and respiratory quinone composition (see below). The 16S rDNA sequence was then compared with all species with validly published names of the most closely related genera, Azoarcus, Thauera and Hydrogenophilus (Springer et al, 1998;Hayashi et al, 1999;Song et al, 1998Song et al, , 1999Song et al, , 2000Song et al, , 2001Reinhold-Hurek & Hurek, 2000;Stöhr et al, 2001;Mechichi et al, 2002), and several other genera in the b-Proteobacteria. The 16S rDNA sequence of strain N2-214 T was not closely related to those of other genera within this subclass, the highest similarities (approx.…”

Sludge bulking impact on relevant bacterial populations in a full-scale municipal wastewater treatment plant

“…These two strains could reduce nitrate to N 2 [29]. Their high percentage in activated sludge in the non-bulking phase suggests that they might have played an important role in the denitrification in the systems.…”

Methylotrophic methanogenesis governs the biogenic coal bed methane formation in Eastern Ordos Basin, China

“…Both SXLL-B11 and SXLL-B13 showed the closest match to the 16S rRNA gene from the cultured organism Thauera sp. (98% identity), which is a denitrifying bacterium and able to degrade aromatic compounds (Mechichi et al 2002;Shinoda et al 2004). Sequences related to the Firmicutes (10.7% of the clones) were clustered into eight phylotypes (Fig.…”