Treatment of simulated wastewater from in situ leaching uranium mining by zerovalent iron and sulfate reducing bacteria

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

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Microbial ecology of sulfate-reducing bacteria in wastewater biofilms analyzed by microelectrodes and fish (fluorescent in situ hybridization) technique

Water Science & Technology ◽

10.2166/wst.1999.0323 ◽

1999 ◽

Vol 39 (7) ◽

pp. 41-47 ◽

Cited By ~ 3

Author(s):

Satoshi Okabe ◽

Hisashi Satoh ◽

Tsukasa Itoh ◽

Yoshimasa Watanabe

Keyword(s):

In Situ Hybridization ◽

Sulfate Reduction ◽

Sulfate Reducing Bacteria ◽

Hybridization Technique ◽

Concentration Profiles ◽

Reduction Zone ◽

Sulfate Reducing ◽

Reducing Bacteria ◽

Culture Dependent

The vertical distribution of sulfate-reducing bacteria (SRB) in microaerophilic wastewater biofilms grown on fully submerged rotating disk reactors (RDR) was determined by the conventional culture-dependent MPN method and in situ hybridization of fluorescently-labelled 16S rRNA-targeted oligonucleotide probes for SRB in parallel. Chemical concentration profiles within the biofilm were also measured using microelectrodes for O2, S2-, NO3- and pH. In situ hybridization revealed that the SRB probe-stained cells were distributed throughout the biofilm even in the oxic surface zone in all states from single scattered cells to clustered cells. The higher fluorescence intensity and abundance of SRB probe-stained cells were found in the middle part of the biofilm. This result corresponded well with O2 and H2S concentration profiles measured by microelectrodes, showing sulfate reduction was restricted to a narrow anaerobic zone located about 500 μm below the biofilm surface. Results of the MPN and potential sulfate reducing activity (culture-dependent approaches) indicated a similar distribution of cultivable SRB in the biofilm. The majority of the general SRB probe-stained cells were hybridized with SRB 660 probe, suggesting that one important member of the SRB in the wastewater biofilm could be the genus Desulfobulbus. An addition of nitrate forced the sulfate reduction zone deeper in the biofilm and reduced the specific sulfate reduction rate as well. The sulfate reduction zone was consequently separated from O2 and NO3- respiration zones. Anaerobic H2S oxidation with NO3- was also induced by addition of nitrate to the medium.

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In Situ Analysis of Sulfate-Reducing Bacteria Related to Desulfocapsa thiozymogenes in the Chemocline of Meromictic Lake Cadagno (Switzerland)

Applied and Environmental Microbiology ◽

10.1128/aem.66.2.820-824.2000 ◽

2000 ◽

Vol 66 (2) ◽

pp. 820-824 ◽

Cited By ~ 37

Author(s):

Mauro Tonolla ◽

Antonella Demarta ◽

Sandro Peduzzi ◽

Dittmar Hahn ◽

Raffaele Peduzzi

Keyword(s):

Sulfate Reducing Bacteria ◽

Comparative Sequence Analysis ◽

Potential Interaction ◽

Meromictic Lake ◽

Rrna Gene ◽

Sulfate Reducing ◽

Sulfur Bacteria ◽

The Family ◽

Reducing Bacteria

ABSTRACT Comparative sequence analysis of a 16S rRNA gene clone library from the chemocline of the meromictic Lake Cadagno (Switzerland) retrieved two clusters of sequences resembling sulfate-reducing bacteria within the family Desulfovibrionaceae. In situ hybridization showed that, similar to sulfate-reducing bacteria of the familyDesulfobacteriaceae, bacteria of one cluster with similarity values to the closest cultured relatives of between 92.6 and 93.1% resembled free cells or cells loosely attached to other cells or debris. Bacteria of the second cluster closely related toDesulfocapsa thiozymogenes DSM7269 with similarity values between 97.9 and 98.4% were generally associated with aggregates of different small-celled phototrophic sulfur bacteria, suggesting a potential interaction between the two groups of bacteria.

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Abundance and spatial organization of Gram-negative sulfate-reducing bacteria in activated sludge investigated by in situ probing with specific 16S rRNA targeted oligonucleotides

FEMS Microbiology Ecology ◽

10.1111/j.1574-6941.1998.tb00459.x ◽

1998 ◽

Vol 25 (1) ◽

pp. 43-61 ◽

Cited By ~ 194

Author(s):

Werner Manz ◽

Michael Eisenbrecher ◽

Thomas R. Neu ◽

Ulrich Szewzyk

Keyword(s):

16S Rrna ◽

Activated Sludge ◽

Spatial Organization ◽

Sulfate Reducing Bacteria ◽

Gram Negative ◽

Sulfate Reducing ◽

Reducing Bacteria

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A Study of the Relative Dominance of Selected Anaerobic Sulfate-Reducing Bacteria in a Continuous Bioreactor by Fluorescence in Situ Hybridization

Microbial Ecology ◽

10.1007/s00248-006-9009-0 ◽

2006 ◽

Vol 53 (1) ◽

pp. 43-52 ◽

Cited By ~ 11

Author(s):

B. Icgen ◽

S. Moosa ◽

S. T. L. Harrison

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Sulfate Reducing Bacteria ◽

Sulfate Reducing ◽

Relative Dominance ◽

Continuous Bioreactor ◽

Reducing Bacteria

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Phylogenetic Identification and Substrate Uptake Patterns of Sulfate-Reducing Bacteria Inhabiting an Oxic-Anoxic Sewer Biofilm Determined by Combining Microautoradiography and Fluorescent In Situ Hybridization

Applied and Environmental Microbiology ◽

10.1128/aem.68.1.356-364.2002 ◽

2002 ◽

Vol 68 (1) ◽

pp. 356-364 ◽

Cited By ~ 77

Author(s):

Tsukasa Ito ◽

Jeppe L. Nielsen ◽

Satoshi Okabe ◽

Yoshimasa Watanabe ◽

Per H. Nielsen

Keyword(s):

In Situ Hybridization ◽

16S Rrna ◽

Electron Acceptor ◽

Fluorescent In Situ Hybridization ◽

Sulfate Reducing Bacteria ◽

Substrate Uptake ◽

Sulfate Reducing ◽

Phylogenetic Identification ◽

Reducing Bacteria

ABSTRACT We simultaneously determined the phylogenetic identification and substrate uptake patterns of sulfate-reducing bacteria (SRB) inhabiting a sewer biofilm with oxygen, nitrate, or sulfate as an electron acceptor by combining microautoradiography and fluorescent in situ hybridization (MAR-FISH) with family- and genus-specific 16S rRNA probes. The MAR-FISH analysis revealed that Desulfobulbus hybridized with probe 660 was a dominant SRB subgroup in this sewer biofilm, accounting for 23% of the total SRB. Approximately 9 and 27% of Desulfobulbus cells detected with probe 660 could take up [14C]propionate with oxygen and nitrate, respectively, as an electron acceptor, which might explain the high abundance of this species in various oxic environments. Furthermore, more than 40% of Desulfobulbus cells incorporated acetate under anoxic conditions. SRB were also numerically important members of H2-utilizing and 14CO2-fixing microbial populations in this sewer biofilm, accounting for roughly 42% of total H2-utilizing bacteria hybridized with probe EUB338. A comparative 16S ribosomal DNA analysis revealed that two SRB populations, related to the Desulfomicrobium hypogeium and the Desulfovibrio desulfuricans MB lineages, were found to be important H2 utilizers in this biofilm. The substrate uptake characteristics of different phylogenetic SRB subgroups were compared with the characteristics described to date. These results provide further insight into the correlation between the 16S rRNA phylogenetic diversity and the physiological diversity of SRB populations inhabiting sewer biofilms.

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APPLICATION OF RAMAN SPECTROSCOPY IN COMPARISON BETWEEN CRYPTIC MICROBIALITES OF RECENT MARINE CAVES AND TRIASSIC PATCH REEFS

Palaios ◽

10.2110/palo.2019.055 ◽

2019 ◽

Vol 34 (8) ◽

pp. 393-403

Author(s):

ADRIANO GUIDO ◽

STEPHEN KERSHAW ◽

FRANCO RUSSO ◽

DOMENICO MIRIELLO ◽

ADELAIDE MASTANDREA

Keyword(s):

Raman Spectroscopy ◽

Microbial Communities ◽

Sulfate Reducing Bacteria ◽

Organic Content ◽

Geological Time ◽

Patch Reefs ◽

Sulfate Reducing ◽

Marine Caves ◽

Reducing Bacteria

ABSTRACT Microbialites are common carbonate structures in cryptic niches of marine environments throughout geological time. In this research we compare the microbialites of small bioconstructions (biostalactites) of modern submarine caves of Sicily with those developed in small crypts of Carnian patch reefs of the Dolomite Mountains (Heiligkreuz Formation, Alpe di Specie) using Raman spectroscopy, a method that allows in situ determination of the organic content of microbial components. This methodology partly solves the uncertainty of geomicrobiological studies that use bulk measurements (i.e., biomarker analyses), which make it difficult to associate mineral precipitates with a specific microbial process. In the modern marine caves, the complex biotic relationships among skeletal organisms (mainly serpulids) and microbial communities produced biostalactites in which microbially induced biomineralization is the consequence of autotrophic and chemoheterotrophic bacterial activities. Sulfate-reducing bacteria, fed by metazoan organic matter, flourish in millimetric oxygen-depleted cavities of the skeletal framework, and induce autochthonous micrite deposition and early stabilization of the biostalactites. Similar processes have been interpreted to induce the deposition of the microbialites in the Upper Triassic patch reefs of the Dolomites. These small shallow water reefs, made up mainly of scleractinian corals, sponges and red algae, hold a skeletal framework rich in millimeter- to centimeter-size cavities, ideal cryptic niches for growth of microbial communities. Specific sulfate-reducing bacteria biomarkers are first identified using bulk measurements obtained by solvent extraction. The subsequent in situ characterization of organic compounds through micro-Raman spectroscopy indicates the same biogeochemical signatures of the microbialites within the cryptic cavities of the biostalactites of modern marine caves as those inside the skeletal framework of Carnian patch reefs. These data, showing the same processes in Triassic and modern cryptic microenvironments, is evidence that the microbially mediated precipitation in confined environments is a process independent of geological time that further investigation may be able to test.

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Community Structure, Cellular rRNA Content, and Activity of Sulfate-Reducing Bacteria in Marine Arctic Sediments

Applied and Environmental Microbiology ◽

10.1128/aem.66.8.3592-3602.2000 ◽

2000 ◽

Vol 66 (8) ◽

pp. 3592-3602 ◽

Cited By ~ 198

Author(s):

Katrin Ravenschlag ◽

Kerstin Sahm ◽

Christian Knoblauch ◽

Bo B. Jørgensen ◽

Rudolf Amann

Keyword(s):

Community Structure ◽

16S Rrna ◽

Sequence Similarity ◽

Blot Hybridization ◽

Sulfate Reducing Bacteria ◽

Slot Blot ◽

Sulfate Reducing ◽

Slot Blot Hybridization ◽

Reducing Bacteria

ABSTRACT The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburgfjorden, Svalbard) was characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes. The SRB community was dominated by members of the Desulfosarcina-Desulfococcus group. This group accounted for up to 73% of the SRB detected and up to 70% of the SRB rRNA detected. The predominance was shown to be a common feature for different stations along the coast of Svalbard. In a top-to-bottom approach we aimed to further resolve the composition of this large group of SRB by using probes for cultivated genera. While this approach failed, directed cloning of probe-targeted genes encoding 16S rRNA was successful and resulted in sequences which were all affiliated with the Desulfosarcina-Desulfococcus group. A group of clone sequences (group SVAL1) most closely related toDesulfosarcina variabilis (91.2% sequence similarity) was dominant and was shown to be most abundant in situ, accounting for up to 54.8% of the total SRB detected. A comparison of the two methods used for quantification showed that FISH and rRNA slot blot hybridization gave comparable results. Furthermore, a combination of the two methods allowed us to calculate specific cellular rRNA contents with respect to localization in the sediment profile. The rRNA contents of Desulfosarcina-Desulfococcus cells were highest in the first 5 mm of the sediment (0.9 and 1.4 fg, respectively) and decreased steeply with depth, indicating that maximal metabolic activity occurred close to the surface. Based on SRB cell numbers, cellular sulfate reduction rates were calculated. The rates were highest in the surface layer (0.14 fmol cell−1day−1), decreased by a factor of 3 within the first 2 cm, and were relatively constant in deeper layers.

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