Showing papers on "Dechloromonas published in 2008"
TL;DR: Results show that the functional diversity of populations capable of U(VI) reduction is dependent upon the choice of electron donor, and that the active FeRB share high sequence identity with Geobacteraceae members cultivated from contaminated subsurface environments.
Abstract: In order to elucidate the potential mechanisms of U(VI) reduction for the optimization of bioremediation strategies, the structure-function relationships of microbial communities were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate. A polyphasic approach was used to assess the functional diversity of microbial populations likely to catalyze electron flow under conditions proposed for in situ uranium bioremediation. The addition of ethanol and glucose as supplemental electron donors stimulated microbial nitrate and Fe(III) reduction as the predominant terminal electron-accepting processes (TEAPs). U(VI), Fe(III), and sulfate reduction overlapped in the glucose treatment, whereas U(VI) reduction was concurrent with sulfate reduction but preceded Fe(III) reduction in the ethanol treatments. Phyllosilicate clays were shown to be the major source of Fe(III) for microbial respiration by using variable-temperature Mossbauer spectroscopy. Nitrate- and Fe(III)-reducing bacteria (FeRB) were abundant throughout the shifts in TEAPs observed in biostimulated microcosms and were affiliated with the genera Geobacter, Tolumonas, Clostridium, Arthrobacter, Dechloromonas, and Pseudomonas. Up to two orders of magnitude higher counts of FeRB and enhanced U(VI) removal were observed in ethanol-amended treatments compared to the results in glucose-amended treatments. Quantification of citrate synthase (gltA) levels demonstrated a stimulation of Geobacteraceae activity during metal reduction in carbon-amended microcosms, with the highest expression observed in the glucose treatment. Phylogenetic analysis indicated that the active FeRB share high sequence identity with Geobacteraceae members cultivated from contaminated subsurface environments. Our results show that the functional diversity of populations capable of U(VI) reduction is dependent upon the choice of electron donor.
101 citations
TL;DR: It is suggested that oxygen is more favorable than nitrate as a primary electron acceptor for PCRB, that PCRB are present at low levels even without perchlorate, and that the presence of per chlorate, even atLow levels relative to nitrate or oxygen, significantly enhances selection forPCRB.
92 citations
TL;DR: The present study describes isolation and genetic characterization of Dechlorospirillum anomalous strain JB116 that belongs to alpha subclass of Proteobacteria that shares 99% 16S rDNA sequence similarity with the type strain D. anomalous strains WD.
17 citations
TL;DR: The study, apart from demonstrating ribotyping as a rapid method of identification of economically important soil microbes, also raised prospects for using artificial consortia for environmental degradation of perchlorate, without apparent domination ofechloromonas spp.
Abstract: Possibility of perchlorate reduction by microbes raises hope for an eco-friendly mode of degradation of this toxic rocket fuel. This study reports 3 isolates (A1, A2 and A3) capable of molybdenum-independent degradation of perchlorate under aerobic conditions. The rate of degradation was the highest when perchlorate concentration was 17 mM, and then 3.2 mM, 4.7 mM and 4.1 mM of perchlorate was reduced by isolates A1, A2 and A3 (respectively) after 72 h at 28 degrees C under aerobic conditions. Presence of perchlorate at a concentration higher than 17 mM resulted in some inhibition of perchlorate reduction. 16S ribosomal RNA gene analysis revealed isolate A1 to be Pseudomonas stutzeri (Proteobacteria) while isolates A2 ad A3 where found to belong to the genus Arthrobacter (Actinobacteria). The study, apart from demonstrating ribotyping as a rapid method of identification of economically important soil microbes, also raised prospects for using artificial consortia for environmental degradation of perchlorate, without apparent domination of Dechloromonas spp. (a group of microbes known for perchlorate remediation in the environment).
12 citations