scholarly journals Salinity Responses of Benthic Microbial Communities in a Solar Saltern (Eilat, Israel)

2004 ◽  
Vol 70 (3) ◽  
pp. 1608-1616 ◽  
Author(s):  
Ketil Bernt S�rensen ◽  
Donald E. Canfield ◽  
Aharon Oren
Keyword(s):  
Sulfate Reduction ◽  
Reduction Rate ◽  
Sulfate Reduction Rate ◽  
Anoxygenic Phototrophs ◽  
Sulfate Reducing ◽  
Oxygen Budget ◽  
Reducing Bacteria ◽  
Increased Activity ◽  
Optimum Salinity

ABSTRACT The salinity responses of cyanobacteria, anoxygenic phototrophs, sulfate reducers, and methanogens from the laminated endoevaporitic community in the solar salterns of Eilat, Israel, were studied in situ with oxygen microelectrodes and in the laboratory in slurries. The optimum salinity for the sulfate reduction rate in sediment slurries was between 100 and 120‰, and sulfate reduction was strongly inhibited at an in situ salinity of 215‰. Nevertheless, sulfate reduction was an important respiratory process in the crust, and reoxidation of formed sulfide accounted for a major part of the oxygen budget. Methanogens were well adapted to the in situ salinity but contributed little to the anaerobic mineralization in the crust. In slurries with a salinity of 180‰ or less, methanogens were inhibited by increased activity of sulfate-reducing bacteria. Unicellular and filamentous cyanobacteria metabolized at near-optimum rates at the in situ salinity, whereas the optimum salinity for anoxygenic phototrophs was between 100 and 120‰.

Interactions between filamentous sulfur bacteria, sulfate reducing bacteria and poly-P accumulating bacteria in anaerobic-oxic activated sludge from a municipal plant

1998 ◽  
Vol 37 (4-5) ◽  
pp. 599-603 ◽  
Author(s):  
Ryoko Yamamoto-Ikemoto ◽  
Saburo Matsui ◽  
Tomoaki Komori ◽  
Edja. Kofi. Bosque-Hamilton
Keyword(s):  
Activated Sludge ◽  
Sulfate Reduction ◽  
Reduction Rate ◽  
Sulfate Reducing Bacteria ◽  
Sulfate Reduction Rate ◽  
Filamentous Bulking ◽  
Sulfate Reducing ◽  
Sulfur Bacteria ◽  
Sulfate Reduction Rates ◽  
Reducing Bacteria

The interactions between filamentous sulfur bacteria (FSB), sulfate reducing bacteria (SRB) and poly-P accumulating bacteria (PAB) in the activated sludge of a municipal plant operated under anaerobic-oxic conditions were examined in batch experiments using return sludge (RAS) and settled sewage. Phosphate release and sulfate reduction occurred simultaneously under anaerobic conditions. SRB were more sensitive to temperature changes than PAB. SRB played an important role in the decomposition of propionate to acetate. When the sulfate reduction rates were high, there was a tendency for the maximum release of phosphate also to be high. This was explained by the fact that PAB utilized the acetate produced by SRB. Sulfur oxidizing bacteria were sensitive to temperature change. When the sulfate reduction rate was high, the sulfide oxidizing rate was also high and filamentous bulking occurred. The results showed that sulfate reduction was a cause of filamentous bulking due to Type 021N that could utilize reduced sulfur.

Ecological interactions among denitrification, poly-P accumulation, sulfate reduction, and filamentous sulfur bacteria in activated sludge

1994 ◽  
Vol 30 (11) ◽  
pp. 201-210 ◽  
Author(s):  
Ryoko Yamamoto-Ikemoto ◽  
Saburo Matsui ◽  
Tomoaki Komori
Keyword(s):  
Sulfate Reduction ◽  
Reduction Rate ◽  
Sodium Molybdate ◽  
Sulfate Reducing Bacteria ◽  
Sulfate Reduction Rate ◽  
Filamentous Bulking ◽  
Sulfate Reducing ◽  
Sulfur Bacteria ◽  
P Accumulation ◽  
Reducing Bacteria

Effects of anoxic-oxic conditions on the growth of sulfate reduction, poly-P accumulation and filamentous sulfur bacteria were examined in the laboratory scale sequential batch reactors. In the anoxic-oxic conditions, denitrification bacteria are dominant. The growth of sulfate reducing bacteria and poly-P accumulating bacteria was suppressed. The number of sulfate reducing bacteria in the activated sludge was below 104 MPN/g MLSS, and the sulfate reduction rate was very low. Filamentous bulking was also suppressed. On the other hand, when nitrate was removed from the artificial wastewater, sulfate reducing bacteria could grow predominantly in the anaerobic conditions. The number of sulfate reducing bacteria was about 106∼107 MPN/g MLSS and the sulfate reduction rate increased (0.17 ∼ 0.21 g SO4/g MLSS·hr). Filamentous bacteria Type 021N increased over 103 cm/mg MLSS. Sodium molybdate was added to the artificial wastewater in order to prevent sulfate reduction. When the concentration of sodium molybdate increased to 980 mg/L, the number of sulfate reducing bacteria decreased to 103 ∼ 104 MPN/g MLSS and the sulfate reduction rate decreased. Filamentous bulking was completely suppressed in these conditions. These results show that sulfate reduction is a main trigger of the filamentous bulking due to Type 021N that can utilize reduced sulfur for an energy source.

Effect of nitrite and nitrate on biogenic sulfide production in sewer biofilms determined by the use of microelectrodes

2003 ◽  
Vol 47 (11) ◽  
pp. 281-288 ◽  
Author(s):  
S. Okabe ◽  
T. Ito ◽  
H. Satoh ◽  
Y. Watanabe
Keyword(s):  
Sulfate Reduction ◽  
Reduction Rate ◽  
Rotating Disk ◽  
Sulfate Reduction Rate ◽  
Reduction Zone ◽  
Sulfate Reducing ◽  
H2s Oxidation ◽  
Rotating Disk Reactors ◽  
Microelectrode Measurements

The effects of O2 and NO3− concentrations on in situ sulfate reduction and sulfide reoxidation in microaerophilic wastewater biofilms grown on rotating disk reactors were investigated by the use of microelectrodes for O2, S2−, NO3−, NO2−, and pH. Microelectrode measurements showed the vertical microzonation of O2 respiration, NO3− respiration, H2S oxidation and SO42− reduction in the biofilms. The microelectrode measurements indicate that sulfate reducing activity was largely restricted to a narrow anaerobic zone located about 500 μm below the biofilm surface. 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 the O2 and NO3− respiration zones. Anaerobic H2S oxidation with NO3− was also induced by addition of nitrate to the medium. Measurements of the reduced inorganic sulfur compounds (FeS, FeS2 and S0), total-Mn and total-Fe in the biofilm indicated that the produced H2S became immediately oxidized with O2, NO3− and other oxidants, mainly ferric/ferrous hydrates. On the basis of the present results, it was estimated that of all sulfide produced, 13% of the sulfide was precipitated by metal ions as FeS and S0 just above the sulfate reduction zone, 65% was anaerobically oxidized to SO42− with NO3− as an electron acceptor and 22% was aerobically oxidized within the biofilm incubated in 70 μmol l−1 of DO and 280 μmol l−1 of NO3−.

scholarly journals Transition from Anaerobic to Aerobic Growth Conditions for the Sulfate-Reducing Bacterium Desulfovibrio oxyclinae Results in Flocculation

2000 ◽  
Vol 66 (11) ◽  
pp. 5005-5012 ◽  
Author(s):  
Pavel Sigalevich ◽  
Eran Meshorer ◽  
Yael Helman ◽  
Yehuda Cohen
Keyword(s):  
Sulfate Reduction ◽  
Reduction Rate ◽  
Growth Yield ◽  
Viable Cell ◽  
Sulfate Reducing Bacteria ◽  
Sulfate Reduction Rate ◽  
Anaerobic Culture ◽  
Cyanobacterial Mat ◽  
Sulfate Reducing ◽  
Reducing Bacteria

ABSTRACT A chemostat culture of the sulfate-reducing bacteriumDesulfovibrio oxyclinae isolated from the oxic layer of a hypersaline cyanobacterial mat was grown anaerobically and then subjected to gassing with 1% oxygen, both at a dilution rate of 0.05 h−1. The sulfate reduction rate under anaerobic conditions was 370 nmol of SO4 2− mg of protein−1 min−1. At the onset of aerobic gassing, sulfate reduction decreased by 40%, although viable cell numbers did not decrease. After 42 h, the sulfate reduction rate returned to the level observed in the anaerobic culture. At this stage the growth yield increased by 180% compared to the anaerobic culture to 4.4 g of protein per mol of sulfate reduced. Protein content per cell increased at the same time by 40%. The oxygen consumption rate per milligram of protein measured in washed cell suspensions increased by 80%, and the thiosulfate reduction rate of the same samples increased by 29% with lactate as the electron donor. These findings indicated possible oxygen-dependent enhancement of growth. After 140 h of growth under oxygen flux, formation of cell aggregates 0.1 to 3 mm in diameter was observed. Micrometer-sized aggregates were found to form earlier, during the first hours of exposure to oxygen. The respiration rate of D. oxyclinaewas sufficient to create anoxia inside clumps larger than 3 μm, while the levels of dissolved oxygen in the growth vessel were 0.7 ± 0.5 μM. Aggregation of sulfate-reducing bacteria was observed within a Microcoleus chthonoplastes-dominated layer of a cyanobacterial mat under daily exposure to oxygen concentrations of up to 900 μM. Desulfonema-like sulfate-reducing bacteria were also common in this environment along with other nonaggregated sulfate-reducing bacteria. Two-dimensional mapping of sulfate reduction showed heterogeneity of sulfate reduction activity in this oxic zone.

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

1999 ◽  
Vol 39 (7) ◽  
pp. 41-47 ◽  
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.

scholarly journals Diversity of Sulfur Isotope Fractionations by Sulfate-Reducing Prokaryotes

2001 ◽  
Vol 67 (2) ◽  
pp. 888-894 ◽  
Author(s):  
Jan Detmers ◽  
Volker Brüchert ◽  
Kirsten S. Habicht ◽  
Jan Kuever
Keyword(s):  
Sulfate Reduction ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Reduction Rate ◽  
Sulfate Reduction Rate ◽  
Dissimilatory Sulfate Reduction ◽  
Systematic Effect ◽  
Sulfate Reducers ◽  
Sulfate Reducing ◽  
Sulfur Isotope Fractionation

ABSTRACT Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0‰. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation. Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction.

scholarly journals Diversity, Activity, and Abundance of Sulfate-Reducing Bacteria in Saline and Hypersaline Soda Lakes

2007 ◽  
Vol 73 (7) ◽  
pp. 2093-2100 ◽  
Author(s):  
Mirjam Foti ◽  
Dimitry Y. Sorokin ◽  
Bart Lomans ◽  
Marc Mussman ◽  
Elena E. Zacharova ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Soda Lakes ◽  
Reduction Rate ◽  
Sulfate Reducing Bacteria ◽  
Sulfur Cycle ◽  
Gene Copy ◽  
Sulfate Reduction Rate ◽  
Hypersaline Lake ◽  
Sulfate Reducing ◽  
Reducing Bacteria

ABSTRACT Soda lakes are naturally occurring highly alkaline and saline environments. Although the sulfur cycle is one of the most active element cycles in these lakes, little is known about the sulfate-reducing bacteria (SRB). In this study we investigated the diversity, activity, and abundance of SRB in sediment samples and enrichment cultures from a range of (hyper)saline soda lakes of the Kulunda Steppe in southeastern Siberia in Russia. For this purpose, a polyphasic approach was used, including denaturing gradient gel electrophoresis of dsr gene fragments, sulfate reduction rate measurements, serial dilutions, and quantitative real-time PCR (qPCR). Comparative sequence analysis revealed the presence of several novel clusters of SRB, mostly affiliated with members of the order Desulfovibrionales and family Desulfobacteraceae. We detected sulfate reducers and observed substantial sulfate reducing rates (between 12 and 423 μmol/dm3 day−1) for most lakes, even at a salinity of 475 g/liter. Enrichments were obtained at salt saturating conditions (4 M Na+), using H2 or volatile fatty acids as electron donors, and an extremely halophilic SRB, strain ASO3-1, was isolated. Furthermore, a high dsr gene copy number of 108 cells per ml was detected in a hypersaline lake by qPCR. Our results indicate the presence of diverse and active SRB communities in these extreme ecosystems.

Competition between methanogenesis and sulfidogenesis in anaerobic wastewater treatment

1998 ◽  
Vol 38 (8-9) ◽  
pp. 317-324 ◽  
Author(s):  
Gong-Ming Zhou ◽  
Herbert H. P. Fang
Keyword(s):  
Wastewater Treatment ◽  
Sulfate Reduction ◽  
Methane Production ◽  
Reduction Rate ◽  
Uasb Reactor ◽  
Sulfate Reduction Rate ◽  
Sulfate Concentration ◽  
Anaerobic Wastewater Treatment ◽  
Sulfate Reducing ◽  
Sulfate Removal

This study was conducted to investigate the methanogenic and sulfidogenic activities of biomass in a UASB reactor treating wastewater containing benzoate (680 mg l−1) and sulfate (increased from 1080 to 2680 mg l−1) at 37°C and 12 hours of hydraulic retention. Results showed that after 120 days of acclimation, sludge consistently removed 99.5% of benzoate regardless of increased sulfate concentrations. Sulfidogenesis gradually out-competed methanogenesis during the acclimation phase, as indicated by the increase of sulfate-reducing efficiency (up to 99%) accompanied by the decrease of methane production. Overall sulfate removal efficiency was limited after the reactor had reached its maximum sulfate reduction rate of 2.1 g S (l d−1). Further increasing sulfate concentration from 1080 mg l−1 to 2680 mg l−1 lowered the sulfate-reducing efficiency from 85% to 39%. Flow of available electrons toward sulfidogenesis increased with the decrease of benzoate concentration, and was only slightly affected by the sulfate concentration or the benzoate/SO42−-S ratio.

scholarly journals Analyses of Spatial Distributions of Sulfate-Reducing Bacteria and Their Activity in Aerobic Wastewater Biofilms

1999 ◽  
Vol 65 (11) ◽  
pp. 5107-5116 ◽  
Author(s):  
Satoshi Okabe ◽  
Tsukasa Itoh ◽  
Hisashi Satoh ◽  
Yoshimasa Watanabe
Keyword(s):  
In Situ Hybridization ◽  
Vertical Distribution ◽  
Reduction Rate ◽  
Sulfate Reducing Bacteria ◽  
Sulfur Cycle ◽  
Sulfate Reducing ◽  
High Sulfate ◽  
Reducing Bacteria ◽  
The Vertical Distribution

ABSTRACT The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O2, H2S, NO2 −, NO3 −, NH4 +, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells (approximately 109 to 1010cells per cm3 of biofilm) were evenly distributed throughout the biofilm, even in the oxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations (approximately 108 to 109 cells per cm3). The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 μm below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 μm), which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate.

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