Pelotomaculum terephthalicum sp. nov. and Pelotomaculum isophthalicum sp. nov.: two anaerobic bacteria that degrade phthalate isomers in syntrophic association with hydrogenotrophic methanogens.
ABSTRACT An anaerobic phthalate isomer-degrading strain (JT(T)) that we previously isolated was characterized. In addition, a strictly anaerobic, mesophilic, syntrophic phthalate isomer-degrading bacterium, designated strain JI(T), was isolated and characterized in this study. Both were non-motile rods that formed spores. In both strains, the optimal growth was observed at temperatures around 37 degrees C and neutral pH. In syntrophic co-culture with the hydrogenotrophic methanogen Methanospirillum hungatei, both strains could utilize two or three phthalate isomers for growth, and produce acetate and methane as end products. Strain JT(T) was able to grow on isophthalate, terephthalate, and a number of low-molecular weight aromatic compounds, such as benzoate, hydroquinone, 2-hydroxybenzoate, 3-hydroxybenzoate, 2,5-dihydroxybenzoate, 3-phenylpropionate in co-culture with M. hungatei. It could also grow on crotonate, hydroquinone and 2,5-dihydroxybenzoate in pure culture. Strain JI(T) utilized all of the three phthalate isomers as well as benzoate and 3-hydroxybenzoate for growth in co-culture with M. hungatei. No substrates were, however, found to support the axenic growth of strain JI(T). Neither strain JT(T) nor strain JI(T) could utilize sulfate, sulfite, thiosulfate, nitrate, fumarate, Fe (III) or 4-hydroxybenzoate as electron acceptor. Phylogenetically, strains JT(T) and JI(T) were relatively close to the members of the genera Pelotomaculum and Cryptanaerobacter in 'Desulfotomaculum lineage I'. Physiological and chemotaxonomic characteristics indicated that the two isolates should be classified into the genus Pelotomaculum, creating two novel species for them. Here, we propose Pelotomaculum terephthalicum sp. nov. and Pelotomaculum isophthalicum sp. nov. for strain JT(T) and strain JI(T), respectively. The type strains are strains JT(T) (= DSM 16121(T )= JCM 11824(T )= NBRC 100523(T)) and JI(T) (= JCM 12282(T) = BAA-1053(T)) for P. terephthalicum and P. isophthalicum, respectively.
Article: Unexpected stability of Bacteroidetes and Firmicutes communities in laboratory biogas reactors fed with different defined substrates.[show abstract] [hide abstract]
ABSTRACT: In the present study, bacterial communities in 200-liter biogas reactors containing liquid manure consecutively fed with casein, starch, and cream were investigated over a period of up to 33 days. A 16S rRNA gene clone library identified Bacteroidetes and Firmicutes as the most abundant bacterial groups in the starting material, at 58.9% and 30.1% of sequences, respectively. The community development of both groups was monitored by real-time PCR and single-strand conformation polymorphism (SSCP) analysis. The Firmicutes and Bacteroidetes communities were unexpectedly stable and hardly influenced by batch-feeding events. The continuous feeding of starch led to community shifts that nevertheless contributed to a stable reactor performance. A longer starving period and a change in the pH value resulted in further community shifts within the Bacteroidetes but did not influence the Firmicutes. Predominant DNA bands from SSCP gels were cloned and sequenced. Sequences related to Peptococcaceae, Cytophagales, and Petrimonas sulfuriphila were found in all samples from all experiments. Real-time PCR demonstrated the abundance of members of the phylum Bacteroidetes and also reflected changes in gene copy numbers in conjunction with a changing pH value and acetate accumulation.Applied and environmental microbiology 01/2012; 78(7):2106-19. · 3.69 Impact Factor
Article: Effect of biowaste sludge maturation on the diversity of thermophilic bacteria and archaea in an anaerobic reactor.[show abstract] [hide abstract]
ABSTRACT: Prokaryotic diversity was investigated near the inlet and outlet of a plug-flow reactor. After analyzing 800 clones, 50 bacterial and 3 archaeal phylogenetic groups were defined. Clostridia (>92%) dominated among bacteria and Methanoculleus (>90%) among archaea. Significant changes in pH and volatile fatty acids did not invoke a major shift in the phylogenetic groups. We suggest that the environmental filter imposed by the saline conditions (20 g liter(-1)) selected a stable community of halotolerant and halophilic prokaryotes.Applied and environmental microbiology 02/2009; 75(8):2566-72. · 3.69 Impact Factor
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ABSTRACT: Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.Microbiology and molecular biology reviews: MMBR 04/2009; 73(1):71-133. · 12.59 Impact Factor