Project description:Polycyclic aromatic hydrocarbons (PAHs) are widely distributed pollutants. As in saturated PAH-contaminated sites oxygen is rapidly depleted, microorganisms able to use these compounds as a carbon source in the absence of molecular oxygen are crucial for their consumption. Here, we described the metabolic pathway for anaerobic degradation of phenanthrene by a sulfate-reducing enrichment culture (TRIP) obtained from a natural asphalt lake. The dominant organism of this culture belongs to the Desulfobacteraceae family of deltaproteobacteria. Proteogenome analysis revealed that the metabolic capacity of this bacterium includes the key enzymes for dissimilatory sulfate reduction, the Embden-Meyerhof-Parnas pathway, a complete tricarboxylic acid cycle as well as the key elements of the Wood-Ljungdahl pathway. Genes encoding enzymes potentially involved in the degradation of phenanthrene were identified in the genome of this bacterium. Two gene clusters were identified encoding a carboxylase enzyme involved in the activation of phenanthrene, as well as genes encoding reductases potentially involved in subsequent ring dearomatization and reduction steps. The predicted metabolic pathways were corroborated by transcriptome and proteome analyses and provide the first metabolic pathway for anaerobic degradation of three-rings PAHs.
Project description:Degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene by anaerobic microorganisms is poorly understood. Strain NaphS2, an anaerobic sulfate reducing marine delta-proteobacterium is capable of using naphthalene and the aromatic compound benzoate, as well as pyruvate, as an electron donors in the presence of sulfate. In order to identify genes involved in the naphthalene degradation pathway, we compared gene expression in NaphS2 during growth on benzoate vs. pyruvate, naphthalene vs. pyruvate, and naphthalene vs benzoate.
2010-07-22 | GSE12323 | GEO
Project description:anaerobic phenanthrene degradation denitrifying enrichment Raw sequence reads
Project description:sulfate-reducing enrichment culture Genome sequencing and assembly
| PRJNA824301 | ENA
Project description:Anaerobic biodegradation of phenanthrene and pyrene by sulfate-reducing enrichment cultures obtained from freshwater lake sediments
Project description:Degradation of polycyclic aromatic hydrocarbons (PAHs) such as naphthalene by anaerobic microorganisms is poorly understood. Strain NaphS2, an anaerobic sulfate reducing marine delta-proteobacterium is capable of using naphthalene and the aromatic compound benzoate, as well as pyruvate, as an electron donors in the presence of sulfate. In order to identify genes involved in the naphthalene degradation pathway, we compared gene expression in NaphS2 during growth on benzoate vs. pyruvate, naphthalene vs. pyruvate, and naphthalene vs benzoate. For each experimental set, aRNA from NaphS2 was labelled Cy5 (experiment) or Cy3(control) with three biological replicates hybridized in duplicate. In addition, because of the size of the predicted genome of NaphS2, ORFs were divided into two separate array designs, designated set1 and set2, such that set1 and set2 represent two separate array designs (probe sets) to be treated separately in statistical analysis.
Project description:Identification of the peptides composing the enriched multisubunit enzymes natively purified from the microbial enrichment, based on gel bands obtained by native electrophoresis. The anaerobic oxidation of alkanes is a microbial process occurring in deep-sea hydrocarbon seeps that plays a key ecological role in these exotic niches. The metabolic capacity of anaerobic ethane oxidation, involving uncharted biochemistry, was reported in two archaeal species depending on sulfate-reducing partner bacteria. This study deciphers the molecular basis of the CO2-generating steps of ethanotrophy by characterising the native archaeal enzymes isolated from a thermophilic enrichment. While other microorganisms couple these steps to ferredoxin reduction, we found that the CO-dehydrogenase and the formylmethanofuran-dehydrogenase are bound to F420-reductase modules. The crystal structures of these multi-metalloenzyme complexes revealed electronic bridges coupling C1-oxidation to F420-reduction. Accordingly, both systems exhibit robust F420-reductase activities, which are not detected in methanogenic or methanotrophic relative organisms. We speculate that the whole catabolism of these archaea is reoriented towards F420-reduction, which facilitates the electron transfer to the sulfate-reducing partner, therefore representing the driving force of ethanotrophy.
Project description:Members of the bacterial phylum Spirochaetes are primarily studied for their commensal and pathogenic roles in animal hosts. However, Spirochaetes are also frequently detected in anoxic hydrocarbon-contaminated environments but their ecological role in such ecosystems has so far remained unclear. Here we provide a functional trait to these frequently detected organisms with an example of a sulfate-reducing, naphthalene-degrading enrichment culture consisting of a sulfate-reducing deltaproteobacterium Desulfobacterium naphthalenivorans and a novel spirochete Rectinema cohabitans. Using a combination of genomic, proteomic, and physiological studies we show that R. cohabitans grows by fermentation of organic compounds derived from biomass from dead cells (necromass). It recycles the derived electrons in the form of H2 to the sulfate-reducing D. naphthalenivorans, thereby supporting naphthalene degradation and forming a simple microbial loop. We provide metagenomic evidence that equivalent associations between Spirochaetes and hydrocarbon-degrading microorganisms are of general importance in hydrocarbon- and organohalide-contaminated ecosystems. We propose that environmental Spirochaetes form a critical component of a microbial loop central to nutrient cycling in subsurface environments. This emphasizes the importance of necromass and H2-cycling in highly toxic contaminated subsurface habitats such as hydrocarbon-polluted aquifers.