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1.
The sulfate-reducing bacteriumDesulfobulbus propionicus oxidized sulfide, elemental sulfur, and sulfite to sulfate with oxygen as electron acceptor. Thiosulfate was reduced and
disproportionated exclusively under anoxic conditions. When small pulses of oxygen were added to washed cells in sulfide-containing
assays, up to 3 sulfide molecules per O2 disappeared transiently. After complete oxygen consumption, part of the sulfide reappeared. The intermediate formed was identified
as elemental sulfur by chemical analysis and turbidity measurements. When excess sulfide was present, sulfur dissolved as
polysulfide. This process was faster in the presence of cells than in their absence. The formation of sulfide after complete
oxygen consumption was due to a disproportionation of elemental sulfur (or polysulfide) to sulfide and sulfate. The uncoupler
tetrachlorosalicylanilide (TCS) and the electron transport inhibitor myxothiazol inhibited sulfide oxidation to sulfate and
caused accumulation of sulfur. In the presence of the electron transport inhibitor 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), sulfite and thiosulfate were formed. During sulfur oxidation at low oxygen concentrations, intermediary formation
of sulfide was observed, indicating disproportionation of sulfur also under these conditions. It is concluded that sulfide
oxidation inD. propionicus proceeds via oxidation to elemental sulfur, followed by sulfur disproportionation to sulfide and sulfate.
Dedicated to Prof. Dr. Dr. h.c. Norbert Pfennig on the occasion of his 70th birthday 相似文献
2.
Seafloor fuel cells made with graphite electrodes generate electricity by promoting electron transfer in response to a natural
voltage difference (−0.7 to −0.8 V) between anoxic sediments and overlying oxic seawater. Geochemical impacts of a seafloor
fuel cell on sediment solids and porewaters were examined to identify the anodic mechanisms and substrates available for current
production. In an estuarine environment with little dissolved sulfide, solid-phase acid volatile sulfide and Cr2+-reducible sulfur minerals decreased significantly toward the anode after 7 months of nearly continuous energy harvesting.
Porewater iron and sulfate increased by millimolar amounts. Scanning electron microscope images showed a biofilm overcoating
the anode, and electron microprobe analyses revealed accumulations of sulfur, iron, silicon and phosphorus at the electrode
surface. Sulfur deposition was also observed on a laboratory fuel cell anode used to generate electricity with only dissolved
sulfide as an electron donor. Moreover, current densities and voltages displayed by these purely chemical cells were similar
to the values measured with field devices. These results indicate that electron transfer to seafloor fuel cells can readily
result in the oxidation of dissolved and solid-phase forms of reduced sulfur producing mainly S0 which deposits at the electrode surface. This oxidation product is consistent with the observed enrichment of bacteria most
closely related to Desulfobulbus/Desulfocapsa genera within the anode biofilm, and its presence is proposed to promote a localized biogeochemical cycle whereby biofilm
bacteria regenerate sulfate and sulfide. This electron-shuttling mechanism may co-occur while these or other bacteria use
the anode directly as a terminal electron acceptor. 相似文献
3.
In this study, biological sulfide removal is investigated in a fed batch bioreactor. In this process, sulfide is converted into elemental sulfur particles as an intermediate in the oxidation of hydrogen sulfide to sulfate. The main product is sulfur at low dissolved oxygen or at high sulfide concentrations and also more sulfates are produced at high dissolved oxygen. According to the carried out reactions, a mathematical model is developed. The model parameters are estimated and the model is validated by comparing with some experimental data. The results show that, the proposed model is in a good agreement with experimental data. According to the experimental result and mathematical model, sulfate and sulfur selectivity are sensitive to the concentration of dissolved oxygen. For sulfide concentration 0.2 (mM) in the bioreactor and dissolved oxygen of 0.5 ppm, only 10% of sulfide load is converted to sulfate, while it is 60% at the same sulfide concentration and dissolved oxygen of 4.5 ppm. At high sulfide load to the bioreactor, the concentration of uneliminated sulfide increases; it leads to more sulfur particle selectivity and consequently, less sulfate selectivity. 相似文献
4.
An N2 strip gas was used in a packed bed sulfate-reducing bioreactor to recover the dissolved sulfide product and improve sulfate
conversion. The highest volumetric productivity obtained was 261 mol H2S m−3 d−1. Lowering the initial pH of the medium from 7 to 6 increased the H2S content of the strip gas from 3.6 to 5.8 mol%. The ratio of strip gas to liquid flow rates (G/L) was found be to a suitable basis for scaling the process. Calculations indicated that modest G/L values (<102) were required to recover the residual dissolved sulfide in a downstream stripping column. 相似文献
5.
In situ experiments were conducted to measure sulfate reduction rates and identify rate-limiting factors in a shallow, alluvial aquifer contaminated with municipal landfill leachate. Single-well, push–pull tests conducted in a well adjacent to the landfill with >8 mM dissolved organic carbon (DOC) exhibited a sulfate reduction rate of 3.2 μmol SO4
−2 (L sediment)−1 day−1, a value in close agreement with laboratory-derived estimates. Identical tests conducted in wells located 90 m downgradient where DOC levels remained high (>3 mM) showed no detectable sulfate consumption, and laboratory assays confirmed this observation. However, the rates of sulfate reduction in sediment samples obtained from this site were three times larger when they were amended with filter-sterilized groundwater from the upgradient location. The effect of various amendments on sulfate reduction rates was further examined in laboratory incubations using sediment collected from the downgradient site amended with 35S sulfate. Unamended sediments showed only weak conversion of the tracer to 35S sulfide (5 to 7 cpm/cm2), whereas the addition of Desulfovibrio cells increased 35S sulfide production to 44 cpm/cm2. However, the application of heat-killed Desulfovibrio had a similar stimulatory effect, as did a lactate amendment. Collectively, these findings indicate that the lack of measurable sulfate reduction at the downgradient site was not due to the absence of the necessary metabolic potential, the presence of lower sulfate concentration, or the quantity of electron donor, but by its biodegradability. The findings also indicate that field bioaugmentation attempts should be interpreted with caution. 相似文献
6.
Sulfate-reducing bacteria (SRB), which cause microbiologically influenced material corrosion under anoxic conditions, form
one of the major groups of microorganisms responsible for the generation of hydrogen sulfide. In this study, which is aimed
at reducing the presence of SRB, a novel alternative approach involving the addition of magnesium peroxide (MgO2) compounds involving the use of reagent-grade MgO2 and a commercial product (ORC™) was evaluated as a means of inhibiting SRB in laboratory batch columns. Different concentrations
of MgO2 were added in the columns when black sulfide sediment had appeared in the columns. The experimental results showed that MgO2 is able to inhibit biogenic sulfide. The number of SRB, the sulfide concentration and the sulfate reducing rate (SRR) were
decreased. ORC™ as an additive was able to decrease more effectively the concentration of sulfide in water and the SRB-control
effect was maintained over a longer time period when ORC™ was used. The level of oxidation–reduction potential (ORP), which
has a linear relationship to the sulfide/sulfate ratio, is a good indicator of SRB activity. As determined by fluorescence
in-situ hybridization (FISH), most SRB growth was inhibited under increasing amounts of added MgO2. The concentration of sulfide reflected the abundance of the SRB. Utilization of organic matter greater than the theoretical
SRB utilization rate indicated that facultative heterotrophs became dominant after MgO2 was added. The results of this study could supply the useful information for further study on evaluating the solution to
biocorrosion problems in practical situations. 相似文献
7.
Simone Dannenberg Michael Kroder Waltraud Dilling Heribert Cypionka 《Archives of microbiology》1992,158(2):93-99
All of fourteen sulfate-reducing bacteria tested were able to carry out aerobic respiration with at least one of the following electron donors: H2, lactate, pyruvate, formate, acetate, butyrate, ethanol, sulfide, thiosulfate, sulfite. Generally, we did not obtain growth with O2 as electron acceptor. The bacteria were microaerophilic, since the respiration rates increased with decreasing O2 concentrations or ceased after repeated O2 additions. The amounts of O2 consumed indicated that the organic substrates were oxidized incompletely to acetate; only Desulfobacter postgatei oxidized acetate with O2 completely to CO2. Many of the strains oxidized sulfite (completely to sulfate) or sulfide (incompletely, except Desulfobulbus propionicus); thiosulfate was oxidized only by strains of Desulfovibrio desulfuricans; trithionate and tetrathionate were not oxidized by any of the strains. With Desulfovibrio desulfuricans CSN and Desulfobulbus propionicus the oxidation of inorganic sulfur compounds was characterized in detail. D. desulfuricans formed sulfate during oxidation of sulfite, thiosulfate or elemental sulfur prepared from polysulfide. D. propionicus oxidized sulfite and sulfide to sulfate, and elemental sulfur mainly to thiosulfate. A novel pathway that couples the sulfur and nitrogen cycles was detected: D. desulfuricans and (only with nitrite) D. propionicus were able to completely oxidize sulfide coupled to the reduction of nitrate or nitrite to ammonia. Cell-free extracts of both strains did not oxidize sulfide or thiosulfate, but formed ATP during oxidation of sulfite (37 nmol per 100 nmol sulfite). This, and the effects of AMP, pyrophosphate and molybdate on sulfite oxidation, suggested that sulfate is formed via the (reversed) sulfate activation pathway (involving APS reductase and ATP sulfurylase). Thiosulfate oxidation with O2 probably required a reductive first step, since it was obtained only with energized intact cells.Abbreviations
CCCP
carbonyl cyanide m-chlorophenylhydrazone
-
APS
adenosine phosphosulfate or adenylyl sulfate 相似文献
8.
F. Valdés P. R. Camiloti R. P. Rodriguez T. P. Delforno J. Carrillo-Reyes M. Zaiat D. Jeison 《Biodegradation》2016,27(2-3):119-130
A novel bioreactor, employing a silicone membrane for microaeration, was studied for partial sulfide oxidation to elemental sulfur. The objective of this study was to assess the feasibility of using an internal silicone membrane reactor (ISMR) to treat dissolved sulfide and to characterize its microbial community. The ISMR is an effective system to eliminate sulfide produced in anaerobic reactors. Sulfide removal efficiencies reached 96 % in a combined anaerobic/microaerobic reactor and significant sulfate production did not occur. The oxygen transfer was strongly influenced by air pressure and flow. Pyrosequencing analysis indicated various sulfide-oxidizing bacteria (SOB) affiliated to the species Acidithiobacillus thiooxidans, Sulfuricurvum kujiense and Pseudomonas stutzeri attached to the membrane and also indicated similarity between the biomass deposited on the membrane wall and the biomass drawn from the material support, supported the establishment of SOB in an anaerobic sludge under microaerobic conditions. Furthermore, these results showed that the reactor configuration can develop SOB under microaerobic conditions and can improve and reestablish the sulfide conversion to elemental sulfur. 相似文献
9.
Post-treatment of anaerobic wastewater was undertaken to biologically oxidize dissolved methane, with the aim of preventing methane emission. The performance of dissolved methane oxidation and competition for oxygen among methane, ammonium, organic matter, and sulfide oxidizing bacteria were investigated using a lab-scale closed-type down-flow hanging sponge (DHS) reactor. Under the oxygen abundant condition of a hydraulic retention time of 2h and volumetric air supply rate of 12.95m(3)-airm(-3)day(-1), greater than 90% oxidation of dissolved methane, ammonium, sulfide, and organic matter was achieved. With reduction in the air supply rate, ammonium oxidation first ceased, after which methane oxidation deteriorated. Sulfide oxidation was disrupted in the final step, indicating that COD and sulfide oxidation occurred prior to methane oxidation. A microbial community analysis revealed that peculiar methanotrophic communities dominating the Methylocaldum species were formed in the DHS reactor operation. 相似文献
10.
Henk M. Jonkers Michael Jansen Marc J. E. C. Van der Maarel H. Van Gemerden 《Archives of microbiology》1999,172(3):150-156
This is the first report describing the complete oxidation of dimethyl sulfide (DMS) to sulfate by an anoxygenic, phototrophic
purple sulfur bacterium. Complete DMS oxidation was observed in cultures of Thiocapsa roseopersicina M11 incubated under oxic/light conditions, resulting in a yield of 30.1 mg protein mmol–1. No oxidation of DMS occurred under anoxic/light conditions. Chloroform, methyl butyl ether, and 3-amino-1,2,4-triazole,
which are specific inhibitors of aerobic DMS oxidation in thiobacilli and hyphomicrobia, did not affect DMS oxidation in strain
M11. This could be due to limited transport of the inhibitors through the cell membrane. The growth yield on sulfide as sole
electron donor was 22.2 mg protein mmol–1 under anoxic/light conditions. Since aerobic respiration of sulfide would have resulted in yields lower than 22 mg protein
mmol–1, the higher yield on DMS under oxic/light conditions suggests that the methyl groups of DMS have served as an additional
carbon source or as an electron donor in addition to the sulfide moiety. The kinetic parameters V
max and K
m for DMS oxidation under oxic/light conditions were 12.4 ± 1.3 nmol (mg protein)–1 min–1 and 2 μM, respectively. T. roseopersicina M11 also produced DMS by cleavage of dimethylsulfoniopropionate (DMSP). Specific DMSP cleavage rates increased with increasing
initial substrate concentrations, suggesting that DMSP lyase was only partly induced at lower initial DMSP concentrations.
A comparison of T. roseopersicina strains revealed that only strain M11 was able to oxidize DMS and cleave DMSP. Both strain M11 and strain 5811 accumulated
DMSP intracellularly during growth, while strain 1711 showed neither of these characteristics. Phylogenetic comparison based
on 16S rRNA gene sequence revealed a similarity of 99.0% between strain M11 and strain 5811, and 97.6% between strain M11
and strain 1711. DMS and DMSP utilization thus appear to be strain-specific.
Received: 26 March 1999 / Accepted: 18 June 1999 相似文献
11.
Sipma J Osuna MB Parshina SN Lettinga G Stams AJ Lens PN 《Applied microbiology and biotechnology》2007,76(2):339-347
Desulfotomaculum carboxydivorans, recently isolated from a full-scale anaerobic wastewater treatment facility, is a sulfate reducer capable of hydrogenogenic
growth on carbon monoxide (CO). In the presence of sulfate, the hydrogen formed is used for sulfate reduction. The organism
grows rapidly at 200 kPa CO, pH 7.0, and 55°C, with a generation time of 100 min, producing nearly equimolar amounts of H2 and CO2 from CO and H2O. The high specific CO conversion rates, exceeding 0.8 mol CO (g protein)−1 h−1, makes this bacterium an interesting candidate for a biological alternative of the currently employed chemical catalytic
water–gas shift reaction to purify synthesis gas (contains mainly H2, CO, and CO2). Furthermore, as D. carboxydivorans is capable of hydrogenotrophic sulfate reduction at partial CO pressures exceeding 100 kPa, it is also a good candidate for
biodesulfurization processes using synthesis gas as electron donor at elevated temperatures, e.g., in biological flue gas
desulfurization. Although high maximal specific sulfate reduction rates (32 mmol (g protein)−1 h−1) can be obtained, its sulfide tolerance is rather low and pH dependent, i.e., maximally 9 and 5 mM sulfide at pH 7.2 and
pH 6.5, respectively. 相似文献
12.
An integrated field and laboratory study was conducted to quantify the effect of environmental determinants on the activity of sulfate reducers in a freshwater aquifer contaminated with petroleum hydrocarbons (PHC). Within the contaminated zone, PHC-supported in␣situ sulfate reduction rates varied from 11.58±3.12 to 636±53 nmol cm−3 d−1 and a linear increase (R
2=0.98) in reduction rate was observed with increasing in situ sulfate concentrations suggesting sulfate limitation. Half-saturation concentration (K
s) for sulfate reduction coupled to PHC mineralization was determined for the first time. At two different sites within the␣aquifer, maximum sulfate reduction rate under␣non-limiting conditions (R
max) was 5,000 nmol cm−3 d−1, whereas the retrieved K
s values were 3.5 and 7.5 mM, respectively. The K
s values are the highest ever reported from a natural environment. Furthermore, the K
s values were significantly higher than in situ sulfate concentrations confirming sulfate limited growth. On addition of lactate and formate, sulfate reduction rate increased indicating that reactivity and bioavailability of organic substrate may also have played a role in rate inhibition in certain parts of the aquifer. Experiments with sulfide amendments show statistically minor decrease in sulfate reduction rates on addition of sulfide and analogous increase in sulfide toxicity with increasing sulfide concentrations (0.5–10 mM) was not apparent. 相似文献
13.
Effect of pH on anoxic sulfide oxidizing reactor performance 总被引:3,自引:1,他引:3
The effects of pH on the performance of anoxic sulfide oxidizing (ASO) reactor were evaluated. Performance was investigated under various operational conditions at influent pH range of 4-11. At the influent pH of 7-7.5 during loading tests and HRT tests, the sulfide oxidation was partial. In general, the amount of sulfate formed decreased with the increasing sulfide and nitrite loadings. The bacterial communities in ASO reactors were more sensitive to acidic pH compared with alkaline pH, as nitrite and sulfide removal rates dropped significantly when exposed to acidic pH 3. High dissolved bisulfide ions, nitrite and excess of sulfate (>300 mg/L) might have inhibited the sulfide oxidation under highly acidic and alkaline conditions in the ASO reactor. Based on sulfide and nitrite removal efficiencies, the ASO reactor can be operated in a wide range of pH, i.e. 5-11. 相似文献
14.
Chunli Zheng Yanfei Zhang Yuandong Liu Anna Wu Lexian Xia Jia Zeng Jianshe Liu Guanzhou Qiu 《Current microbiology》2009,58(6):586-592
Adenosine 5′-phosphosulfate (APS) reductase is a key enzyme involved in the pathways of sulfate reduction and sulfide oxidation
in the biological sulfur cycle. In this study, the gene of APS reductase from Acidithiobacillus ferrooxidans was cloned and expressed in Escherichia coli, the soluble protein was purified by one-step affinity chromatography to apparent homogeneity. The molecular mass of the
recombinant APS reductase was determined to be 28 kDa using SDS-PAGE. According to optical and EPR spectra results of the
recombinant protein confirmed that the iron–sulfur cluster inserted into the active site of the protein. Site-directed mutation
for the enzyme revealed that Cys110, Cys111, Cys193, and Cys196 were in ligation with the iron–sulfur cluster. The [Fe4S4] cluster could be assembled in vitro, and exhibited electron transport and redox catalysis properties. As we know so far,
this is the first report of expression in E. coli of APS reductase from A. ferrooxidans. 相似文献
15.
M. I. H. Aleem 《Plant and Soil》1975,43(1-3):587-607
Summary Aspects of the biochemistry of the oxidation of inorganic sulfur compounds are discussed in thiobacilli but chiefly inThiobacillus denitrificans. Almost all of the thiobacilli (e.g. T. denitrificans, T. neapolitanus, T. novellus, andThiobacillus A
2) were capable of producing approximately 7.5 moles of sulfuric acid aerobically from 3.75 moles of thiosulfate per gram of
cellular protein per hr. By far the most prolific producer of sulfuric acid (or sulfates) from the anaerobic thiosulfate oxidation
with nitrates wasT. denitrificans which was capable of producing 15 moles of sulfates from 7.5 moles of thiosulfate with concomitant reduction of 12 moles
of nitrate resulting in the evolution of 6 moles of nitrogen gas/g protein/hr. The oxidation of sulfide was mediated by the
flavo-protein system and cytochromes ofb, c, o, anda-type. This process was sensitive to flavoprotein inhibitors, antimycin A, and cyanide. The aerobic thiosulfate oxidation
on the other hand involved cytochromec : O2 oxidoreductase region of the electron transport chain and was sensitive to cyanide only. The anaerobic oxidation of thiosulfate
byT. denitrificans, however, was severely inhibited by the flavoprotein inhibitors because of the splitting of the thiosulfate molecule into
the sulfide and sulfite moieties produced by the thiosulfate-reductase. Accumulation of tetrathionate and to a small extent
trithionate and pentathionate occurred during anaerobic growth ofT. denitrificans. These polythionates were subsequently oxidized to sulfate with the concomitant reduction of nitrate to N2. Intact cell suspensions catalyzed the complete oxidation of sulfide, thiosulfate, tetrathionate, and sulfite to sulfate
with the stoichiometric reduction of nitrate, nitrite, nitric oxide, and nitrous oxide to nitrogen gas thus indicating that
NO2
−, NO, and N2O are the possible intermediates in the denitrification of nitrate. This process was mediated by the cytochrome electron transport
chain and was sensitive to the electron transfer inhibitors. The oxidation of sulfite involved cytochrome-linked sulfite oxidase
as well as the APS-reductase pathways. The latter was absent inT. novellus andThiobacillus A
2. In all of the thiobacilli the inner as well as the outer sulfur atoms of thiosulfate were oxidized at approximately the
same rate by intact cells. The sulfide oxidation occurred in two stages: (a) a cellular-membrane-associated initial and rapid
oxidation reaction which was dependent upon sulfide concentration, and (b) a slower oxidation reaction stage catalyzed by
the cellfree extracts, probably involving polysulfides. InT. novellus andT. neapolitanus the oxidation of inorganic sulfur compounds is coupled to energy generation through oxidative phosphorylation, however, the
reduction of pyridine nucleotides by sulfur compounds involved an energy-linked reversal of electron transfer.
Paper read at the Symposium on the Sulphur Cycle, Wageningen, May 1974. Summary already inserted on p. 189 of the present
volume. 相似文献
16.
Terminal Processes in the Anaerobic Degradation of an Algal-Bacterial Mat in a High-Sulfate Hot Spring 总被引:7,自引:7,他引:0
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The algal-bacterial mat of a high-sulfate hot spring (Bath Lake) provided an environment in which to compare terminal processes involved in anaerobic decomposition. Sulfate reduction was found to dominate methane production, as indicated by comparison of initial electron flow through the two processes, rapid conversion of [2-14C]acetate to 14CO2 and not to 14CH4, and the lack of rapid reduction of NaH14CO3 to 14CH4. Sulfate reduction was the dominant process at all depth intervals, but a marked decrease of sulfate reduction and sulfate-reducing bacteria was observed with depth. Concurrent methanogenesis was indicated by the presence of viable methanogenic bacteria and very low but detectable rates of methane production. A marked increased in methane production was observed after sulfate depletion despite high concentrations of sulfide (>1.25 mM), indicating that methanogenesis was not inhibited by sulfide in the natural environment. Although a sulfate minimum and sulfide maximum occurred in the region of maximal sulfate reduction, the absence of sulfate depletion in interstitial water suggests that methanogenesis is always severely limited in Bath Lake sediments. Low initial methanogenesis was not due to anaerobic methane oxidation. 相似文献
17.
《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,757(1):31-37
A sensitive and reliable method was developed for the determination of hydrogen sulfide and acid-labile sulfur (ALS) in animal tissues using gas chromatography with flame photometric detector (GC-FPD) and ion chromatography (IC). Hydrogen sulfide trapped in alkaline solution was determined by GC-FPD as hydrogen sulfide or by IC as sulfate after oxidation with hydrogen peroxide. Sodium sulfide used as a source of hydrogen sulfide was standardized by IC. Fresh rat liver and heart tissues contained 112.2±23.0 and 274.1±34.6 nmol/g of ALS respectively. Free hydrogen sulfide was not detected. 相似文献
18.
Inorganic sulfur turnover was examined in oligohaline (salinity < 2 g kg-1) Chesapeake Bay sediments during the summer. Cores incubated for < 3 hr exhibited higher sulfate reduction (SR) rates (13–58
mmol m-2 d-1) than those incubated for 3–8 hr (3–8 mmol m-2 d-1). SR rates (determined with35SO
4
2-
) increased with depth over the top few cm to a maximum at 5 cm, just beneath the boundary between brown and black sediment.
SR rates decreased below 5 cm, probably due to sulfate limitation (sulfate < 25 μM). Kinetic experiments yielded an apparent
half-saturating sulfate concentration (Ks) of 34 μM, ≈ 20-fold lower than that determined for sediments from the mesohaline region of the estuary. Sulfate loss from
water overlying intact cores, predicted on the basis of measured SR rates, was not observed over a 28-hr incubation period.
Reduction of35SO
4
2-
during diffusion experiments with intact core segments from 0–4 and 5–9 cm horizons was less than predicted by non-steady
state diagenetic models based on35SO
4
2-
reduction in whole core injection experiments. The results indicate that net sulfate flux into sediments was an order of
magnitude lower than the gross sulfur turnover rate. Solid phase reduced inorganic sulfur concentrations were only 2–3 times
less than those in sediments from the mesohaline region of the Bay, despite the fact that oligohaline bottom water sulfate
concentrations were 10-fold lower. Our results demonstrate the potential for rapid SR in low salinity estuarine sediments,
which are inhabited by sulfate-reducing bacteria with a high affinity for sulfate, and in which sulfide oxidation processes
replenish the pore water sulfate pool on a time scale of hours. 相似文献
19.
In situ microsensor measurements were combined with biogeochemical methods to determine oxygen, sulfur, and carbon cycling in microbial mats growing in a solar saltern (Salin-de-Giraud, France). Sulfate reduction rates closely followed the daily temperature changes and were highest during the day at 25°C and lowest during the night at 11°C, most probably fueled by direct substrate interactions between cyanobacteria and sulfate-reducing bacteria. Sulfate reduction was the major mineralization process during the night and the contribution of aerobic respiration to nighttime DIC production decreased. This decrease of aerobic respiration led to an increasing contribution of sulfide (and iron) oxidation to nighttime O2 consumption. A peak of elemental sulfur in a layer of high sulfate reduction at low sulfide concentration underneath the oxic zone indicated anoxygenic photosynthesis and/or sulfide oxidation by iron, which strongly contributed to sulfide consumption. We found a significant internal carbon cycling in the mat, and sulfate reduction directly supplied DIC for photosynthesis. The mats were characterized by a high iron content of 56 mol Fe cm–3, and iron cycling strongly controlled the sulfur cycle in the mat. This included sulfide precipitation resulting in high FeS contents with depth, and reactions of iron oxides with sulfide, especially after sunset, leading to a pronounced gap between oxygen and sulfide gradients and an unusual persistence of a pH peak in the uppermost mat layer until midnight. 相似文献
20.
Balk M Weijma J Goorissen HP Ronteltap M Hansen TA Stams AJ 《Applied microbiology and biotechnology》2007,73(5):1203-1211
A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65°C with methanol as sole
energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration
of 200 mg l−1, while on H2/CO2, no apparent inhibition occurred up to a concentration of 500 mg l−1. When strain WW1 was co-cultured under the same conditions with the methanol-utilizing, non-sulfate-reducing bacteria, Thermotoga lettingae and Moorella mulderi, both originating from the same bioreactor, growth and sulfide formation were observed up to 430 mg l−1. These results indicated that in the co-cultures, a major part of the electron flow was directed from methanol via H2/CO2 to the reduction of sulfate to sulfide. Besides methanol, acetate, and hydrogen, strain WW1 was also able to use formate,
malate, fumarate, propionate, succinate, butyrate, ethanol, propanol, butanol, isobutanol, with concomitant reduction of sulfate
to sulfide. In the absence of sulfate, strain WW1 grew only on pyruvate and lactate. On the basis of 16S rRNA analysis, strain
WW1 was most closely related to Desulfotomaculum thermocisternum and Desulfotomaculum australicum. However, physiological properties of strain WW1 differed in some aspects from those of the two related bacteria. 相似文献