Presence Of Sulfate-reducing Bacteria Research Articles

Microbial corrosion of X52 pipeline steel under soil with varied thicknesses soaked with a simulated soil solution containing sulfate-reducing bacteria and the associated galvanic coupling effect

In this work, corrosion of an X52 pipeline steel under soil layers with varied thicknesses soaked with a simulated soil solution was investigated in the absence and presence of sulfate-reducing bacteria (SRB) by weight-loss testing, bio-testing, electrochemical measurements and surface analysis techniques. Results demonstrate that, in anaerobic, sterile soil solutions, the presence of a soil layer on the steel surface accelerates the steel corrosion, with the corrosion rate increasing from 0.01 mm/y for uncovered steel to an average of 0.04 mm/y when the soil layer thickness exceeds 5 mm. The presence of SRB in the soil solution increases remarkably the corrosion of bare steel, with an average corrosion rate up to 0.68 mm/y. However, the presence of a layer of soil on the steel surface decreases the steel corrosion. As the soil layer thickness increases, the corrosion rate further decreases, along with the decreased counts of sessile SRB cells on the steel surface. This is attributed to the blocking effect of the soil layer on transport of SRB cells and nutrients towards the steel surface. A galvanic coupling effect exists between bare steel and the soil-covered steel, where SRB contribute to the galvanic corrosion effect. The galvanic current measured in the presence of SRB is considerably higher than that in the absence of SRB.

Mechanistic aspects of microbially influenced corrosion of X52 pipeline steel in a thin layer of soil solution containing sulphate-reducing bacteria under various gassing conditions

Corrosion of X52 pipeline steel under a thin layer of soil solution containing sulphate-reducing bacteria (SRB) was investigated under various gassing conditions (i.e., air, nitrogen and 5% CO2). In the sterile solution, the steel suffers from the highest corrosion rate upon air-purging. In the presence of SRB, the steel corrosion is affected by the aeration of the solution layer. While the oxygen inhibits the bacterial growth, the SRB growth and biofilm formation are enhanced in the presence of CO2, accelerating the steel corrosion. There is a synergism of SRB and CO2 on the steel corrosion.

Sensitive and Rapid Detection of Sulfate-Reducing Bacteria in Jet Fuel by Loop-Mediated Isothermal Amplification Combined with Lateral Flow Dipstick

The existence of Sulfate-Reducing Bacteria (SRB) is one of the significant reasons for the Microbially Influenced Corrosion (MIC) of jet fuel. Especially for the jet fuel stored by military, since jet fuel is stored in the tank for a long time, some oxygen-consuming bacteria such as Amorphotheca resinae and Bacillus Cohn can consume oxygen and generate organic acids at the oil-water interface of the tank bottom. This causes anaerobic SRB flourish in fuel tanks. In this study, a loop-mediated isothermal amplification (LAMP) combined with a chromatographic Lateral Flow Dipstick (LFD) assay was established to detect the SRB. Four groups of LAMP primers were designed and synthesized to target dsrB (dissimilatory sulfite reductase β-subunit) genes in SRB.LAMP-LFD can detect 121 fg/μL of SRB DNA within 35 min. The detection limit of this method is 1000 times more sensitive than the conventional PCR and shortens the detection time greatly. This method is negative for other eight common bacteria species in jet fuel, indicating that the method has high specificity. In summary, this method can be used to detect the presence of SRB in jet fuel.

Kinetic Properties of the Passive Film on Copper in the Presence of Sulfate-Reducing Bacteria

Copper specimens were exposed to Sulfate-Reducing Bacteria (SRB) for 10 months under the conditions corresponding to the final disposal of high-level nuclear waste. In-situ electrochemical impedance spectroscopy (EIS) measurements were carried out to characterize the surface-environment interface after various times of exposure. The EIS results are interpreted in terms of the Point Defect Model (PDM), in order to obtain kinetic information on the formation of the Cu2S passive film. The standard rate constant and the rate constants for the surface reactions revealed that the Cu2S layer is a p-type semiconductor. The diffusion constant for cation vacancies in the barrier layer and the average bulk cation vacancy concentration in the barrier layer were found to be on the orders of 10−13 cm2⋅s−1 and 1022 cm−3, respectively, i.e., both slightly higher than reported in literature for corresponding electrochemically developed Cu2S layers. The electric field strength was approximately 3⋅105 Vcm−1 at all measurement points. These results are presented and discussed in this work in the light of storage of high-level nuclear waste.

Corrosion of antibacterial Cu-bearing 316L stainless steels in the presence of sulfate reducing bacteria

Corrosion of two types of antibacterial Cu-bearing 316L stainless steel was investigated in a medium containing sulfate reducing bacteria (SRB) by various surface characterization and electrochemical measurements. The addition of Cu does not improve the resistance of 316L stainless steel to microbiologically influenced corrosion. The anticorrosion performance of 316L-Cu-A is better than 316L-Cu-B, which is believed to be associated with the addition of elements La and Ce, rather than Cu, in the steel. The Cu ions react with sulfides produced by SRB to produce copper sulfide on the steel surface, increasing corrosion of the Cu-bearing stainless steels.

Unintended Laboratory-Driven Evolution Reveals Genetic Requirements for Biofilm Formation by Desulfovibrio vulgaris Hildenborough.

ABSTRACTBiofilms of sulfate-reducing bacteria (SRB) are of particular interest as members of this group are culprits in corrosion of industrial metal and concrete pipelines as well as being key players in subsurface metal cycling. Yet the mechanism of biofilm formation by these bacteria has not been determined. Here we show that two supposedly identical wild-type cultures of the SRB Desulfovibrio vulgaris Hildenborough maintained in different laboratories have diverged in biofilm formation. From genome resequencing and subsequent mutant analyses, we discovered that a single nucleotide change within DVU1017, the ABC transporter of a type I secretion system (T1SS), was sufficient to eliminate biofilm formation in D. vulgaris Hildenborough. Two T1SS cargo proteins were identified as likely biofilm structural proteins, and the presence of at least one (with either being sufficient) was shown to be required for biofilm formation. Antibodies specific to these biofilm structural proteins confirmed that DVU1017, and thus the T1SS, is essential for localization of these adhesion proteins on the cell surface. We propose that DVU1017 is a member of the lapB category of microbial surface proteins because of its phenotypic similarity to the adhesin export system described for biofilm formation in the environmental pseudomonads. These findings have led to the identification of two functions required for biofilm formation in D. vulgaris Hildenborough and focus attention on the importance of monitoring laboratory-driven evolution, as phenotypes as fundamental as biofilm formation can be altered.

Corrosion Behavior of Cupronickel Alloy in Simulated Seawater in the Presence of Sulfate-Reducing Bacteria

The corrosion behavior of cupronickel alloy immersed in the simulated seawater in or without the presence of sulfate-reducing bacteria (SRB) was studied. The results of scanning electronic microscopy and electrochemical impedance spectra reveal that corrosion of the sample immersed in the simulated seawater with SRB was more serious than that immersed in the simulated seawater without SRB. The atomic force microscopy images show that after immersion for 15 days, the surface roughness of the sample in the simulated seawater with SRB was higher than that of the sample in the simulated seawater without SRB. The analysis of confocal laser scanning microscopy indicates that the average depth of the pits on the surface of the sample in the simulated seawater with SRB was almost twice deeper than that of the sample in the simulated seawater without SRB.

The effect of sulfate-reducing bacteria on hydrogen permeation of X80 steel under cathodic protection potential

The pipelines buried underground are always influenced by sulfate-reducing bacteria (SRB) and cathodic protection (CP). The literature had recorded the fracture accidents of buried pipeline caused by SRB and cathodic potential. To investigate whether SRB can influence the hydrogen damage of pipeline steel under cathodic potential, the synergistic effect of SRB and cathodic potential on hydrogen permeation behavior of X80 steel was investigated by electrochemical tests and optical observation, by which both the growth cycle of microorganism and the applied potential are considered. The results showed that the hydrogen permeation current density of X80 steel in SRB-inoculated solution was three times higher than that without SRB. Serious hydrogen blistering on the surface of specimen was observed in the presence of SRB. The permeation current increases with the negative shifting of the applied cathodic potential in SRB-inoculated solution, which is attributed to the cathodic polarization and the metabolic activities of SRB. The research indicated that the hydrogen damage of pipeline is more likely occurred in the environments with SRB under a more negative cathodic CP potential.

Profiling of Sulfate-Reducing Bacteria in an Offshore Oil Reservoir Using Phospholipid Fatty Acid (PLFA) Biomarkers

PLFA analysis was conducted to profile microorganisms and trace sulfate-reducing bacteria (SRB) in water samples from an offshore oil reservoir. From the results of spiked phospholipid standards, more than 90% of the phospholipids were recovered before the treatment of fatty acid methyl ester (FAME) derivatization while the relative standard deviations (RSD) were below 8.0%. The water samples from the injection well and four producing wells exhibited various reducing conditions and were further subjected to PLFA analysis. Fourteen kinds of phospholipid fatty acids were detected in the five wellbores and the concentrations of total fatty acids ranged from 368.4 to 3468.9 ng/L. Possible SRB biomarkers and significant phospholipid fatty acids associated with SRB including C14:0, i-C15:0, a-C15:0, C15:0, C16:1 (cis-9), C17:0, C18:1 (cis-9), C18:1 (cis-11) and C18:0 were selected for determining the presence of SRB species and evaluating the sulfate-related microbial biomass. The possible existence of SRB genera Desulfobacter, Desulfotomaculum, Desulfovibrio, and sulfur-oxidizing bacteria (SOB) in the reservoir were proposed based on PLFA profiles. The highest biomass was found in the most reducing well where very limited SOB biomarkers were found. Results indicated that the presence of SRB and SOB species was closely associated with the redox environment of the reservoir wellbores. The species distribution patterns were interpreted to elucidate the biological souring process.

Sulphate-reducing bacteria from ulcerative colitis patients induce apoptosis of gastrointestinal epithelial cells

The human microbiome consists of a multitude of bacterial genera and species which continuously interact with one another and their host establishing a metabolic equilibrium. The dysbiosis can lead to the development of pathology, such as inflammatory bowel diseases. Sulfide-producing prokaryotes, including sulphate-reducing bacteria (SRB) constituting different genera, including the Desulfovibrio, are commonly detected within the human microbiome recovered from fecal material or colonic biopsy samples. It has been proposed that SRB likely contribute to colonic pathology, for example ulcerative colitis (UC).The interaction of SRB with the human colon and intestinal epithelial cell lines has been investigated using Desulfovibrio indonesiensis as a model mono-culture and in a co-culture with E. coli isolate, and with SRB consortia from human biopsy samples.We find that D. indonesiensis, whether as a mono- or co-culture, was internalized and induced apoptosis in colon epithelial cells. This effect was enhanced in the presence of E. coli. The SRB combination obtained through enrichment of biopsies from UC patients induced apoptosis of a human intestinal epithelial cell line. This response was not observed in SRB enrichments from healthy (non-UC) controls. Importantly, apoptosis was detected in epithelial cells from UC patients and was not seen in epithelial cells of healthy donors. Furthermore, the antibody raised against exopolysaccharides (EPS) of D. indonesiensis cross reacted with the SRB population from UC patients but not with the SRB combination from non-UC controls. This study reinforces a correlation between the presence of sulphate-reducing bacteria and an inflammatory response in UC sufferers.

Microbial Diversity in a Hypersaline Sulfate Lake: A Terrestrial Analog of Ancient Mars.

Life can persist under severe osmotic stress and low water activity in hypersaline environments. On Mars, evidence for the past presence of saline bodies of water is prevalent and resulted in the widespread deposition of sulfate and chloride salts. Here we investigate Spotted Lake (British Columbia, Canada), a hypersaline lake with extreme (>3 M) levels of sulfate salts as an exemplar of the conditions thought to be associated with ancient Mars. We provide the first characterization of microbial structure in Spotted Lake sediments through metagenomic sequencing, and report a bacteria-dominated community with abundant Proteobacteria, Firmicutes, and Bacteroidetes, as well as diverse extremophiles. Microbial abundance and functional comparisons reveal similarities to Ace Lake, a meromictic Antarctic lake with anoxic and sulfidic bottom waters. Our analysis suggests that hypersaline-associated species occupy niches characterized foremost by differential abundance of Archaea, uncharacterized Bacteria, and Cyanobacteria. Potential biosignatures in this environment are discussed, specifically the likelihood of a strong sulfur isotopic fractionation record within the sediments due to the presence of sulfate reducing bacteria. With its high sulfate levels and seasonal freeze-thaw cycles, Spotted Lake is an analog for ancient paleolakes on Mars in which sulfate salt deposits may have offered periodically habitable environments, and could have concentrated and preserved organic materials or their biomarkers over geologic time.

Effect of interfacial film on the corrosion behaviour of X80 pipeline steel in a neutral soil environment containing sulphate-reducing bacteria

AbstractX80 pipeline steel is inevitably corroded by sulphate-reducing bacteria (SRB) in soil. Corrosion-induced damage to the pipeline steel could result in serious consequences. Studies have shown the critical role of interfacial film in SRB-induced corrosion. However, the specific effect of interfacial film was not examined. The effect of film on the corrosion of X80 steel in neutral soil environment was determined using scanning electron microscopy, energy-dispersive spectroscopy, and electrochemical impedance spectroscopy. The structure and electrochemical characteristics of the surface film of X80 steel were examined in the presence of SRB in Shenyang soil. The results showed that, at the beginning of immersion (14 h), the steel surface mainly adsorbed the SRB biofilm, and the biofilm slowed down the corrosion reaction. A small amount of the biofilm and corrosion product film was observed on the electrode surface after immersion for 14–48 h. The corrosion product film destroyed the protection of the biofilm, increasing corrosion. After immersion for 48 h, the corrosion product contents and polarisation resistance increased. After immersion for 240 h, a dense corrosion product film formed on the sample surface, showing the least corrosion. The protective effect of corrosion products on X80 steel was much greater than that of the biofilm.

Reduction of adsorbed As(V) on nano-TiO2 by sulfate-reducing bacteria

Reduction of surface-bound arsenate [As(V)] and subsequent release into the aqueous phase contribute to elevated As in groundwater. However, this natural process is not fully understood, especially in the presence of sulfate-reducing bacteria (SRB). Gaining mechanistic insights into solid-As(V)-SRB interactions motivated our molecular level study on the fate of nano-TiO2 bound As(V) in the presence of Desulfovibrio vulgaris DP4, a strain of SRB, using incubation and in situ ATR-FTIR experiments. The incubation results clearly revealed the reduction of As(V), either adsorbed on nano-TiO2 or dissolved, in the presence of SRB. In contrast, this As(V) reduction was not observed in abiotic control experiments where sulfide was used as the reductant. Moreover, the reduction was faster for surface-bound As(V) than for dissolved As(V), as evidenced by the appearance of As(III) at 45h and 75h, respectively. ATR-FTIR results provided direct evidence that the surface-bound As(V) was reduced to As(III) on TiO2 surfaces in the presence of SRB. In addition, the As(V) desorption from nano-TiO2 was promoted by SRB relative to abiotic sulfide, due to the competition between As(V) and bacterial phosphate groups for TiO2 surface sites. This competition was corroborated by the ATR-FTIR analysis, which showed inner-sphere surface complex formation by bacterial phosphate groups on TiO2 surfaces. The results from this study highlight the importance of indirect bacteria-mediated As(V) reduction and release in geochemical systems.

Stress Corrosion Cracking Behavior of X80 Pipeline Steel in Acid Soil Environment with SRB

Self-designed experimental device was adopted to ensure the normal growth of sulphate-reducing bacteria (SRB) in sterile simulated Yingtan soil solution. Stress corrosion cracking (SCC) behavior of X80 pipeline steel in simulated acid soil environment was investigated by electrochemical impedance spectroscopy, slow strain rate test, and scanning electron microscope. Results show that the presence of SRB could promote stress corrosion cracking susceptibility. In a growth cycle, polarization resistance first presents a decrease and subsequently an increase, which is inversely proportional to the quantities of SRB. At 8 days of growth, SRB reach their largest quantity of 1.42 × 103 cells/g. The corrosion behavior is most serious at this time point, and the SCC mechanism is hydrogen embrittlement. In other SRB growth stages, the SCC mechanism of X80 steel is anodic dissolution. With the increasing SRB quantities, X80 steel is largely prone to SCC behavior, and the effect of hydrogen is considerably obvious.

Substrate Availability, pH, and Temperature Influence Methanogenesis and Mild Steel Corrosion

ABSTRACTSolid deposits of corroded pipelines in the Niger Delta were analyzed both chemically and microbiologically. The addition of substrate, especially acetate, significantly stimulated the methane production ranging from 0.85 to 1.60 mmole compared with 0.65 mmole of the control. Acetotrophic and hydrogenotrophic methanogens had their optimal methane production and corrosion rate at pH 5.5. All three types of methanogens produced the most methane at 37°C. Methane production by methanogens correlated strongly with corrosion rate. Pyrosequencing surveys show dominance of acetotrophic, hydrogenotrophic, and methylotrophic methanogens in the samples with no significant presence of sulfate-reducing bacteria (SRB), most likely due to the presence of the biocide, tetrakis-hydroxymethyl phosphonium sulfate. Our study shows that methanogens were one possible cause of pipeline failures in samples from the Niger Delta without the syntrophic association with SRB.

Carbon steel corrosion induced by sulphate-reducing bacteria in artificial seawater: electrochemical and morphological characterizations

In this work, the corrosion behavior of carbon steel AISI 1020 was evaluated in artificial seawater in the presence of mixed sulfate-reducing bacteria (SRB) culture isolated from the rust of a pipeline. The corrosion evaluation was performed by electrochemical techniques (open circuit potential (E ocp ), polarization curves and electrochemical impedance spectroscopy (EIS)), while the formation of a biofilm and corrosion products were observed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). The presence of SRB in the medium shifted the open circuit potential to more positive values and increased the corrosion rate of the steel. Electrochemical and morphological techniques confirmed the presence of a biofilm on the steel surface. EDS spectra data showed the presence of sulfur in the corrosion products. After removing the biofilm, localized corrosion was observed on the surface, confirming that localized corrosion had occurred. The biogenic sulfide may lead to the formation of galvanic cells and contributes to cathodic depolarization. Keywords : sulphate-reducing bacteria, biofilm formation; carbon steel, electrochemical impedance spectroscopy, morphological characterization.

Corrosion of copper in oxygen-deficient groundwater with and without deep bedrock micro-organisms: Characterisation of microbial communities and surface processes

Copper specimens were exposed to oxygen-deficient artificial groundwater in the presence and absence of micro-organisms enriched from the deep bedrock of the planned nuclear waste repository site at Olkiluoto island on the western coast of Finland. During the exposure periods of 4 and 10 months, the copper specimens were subjected to electrochemical measurements. The biofilm developed on the specimens and the water used in the exposures were subjected to microbiological analyses. Changes in the water chemistry were also determined and surfaces of the copper specimens were characterized with respect to the morphology and composition of the formed corrosion products. The results showed that under biotic conditions, redox of the water and open circuit potential (OCP) of the copper specimens were generally negative and resulted in the build-up of a copper sulphide, Cu2S, layer due to the activity of sulphate-reducing bacteria (SRB) that were included in the system. In the 4-month test, the electrochemical behaviour of the specimens changed during the exposure and alphaproteobactria Rhizobiales were the dominant bacterial group in the biofilm where the highest corrosion rate was observed. In the 10-month test, however, deltaproteobacteria SRB flourished and the initial electrochemical behaviour and the low corrosion rate of the copper were retained until the end of the test period. Under abiotic conditions, the positive water redox potential and specimen OCP correlated with the formation of copper oxide, Cu2O. Furthermore, in the absence of SRB, Cu2O provided slightly inferior protection against corrosion compared to that by Cu2S in the presence of SRB. The obtained results show that the presence of microorganisms may enhance the passivity of copper. In addition, the identification of key microbial species, such as SRB thriving on copper for long time periods, is important for successful prediction of the behaviour of copper.

Influence of Sulfate-Reducing Bacteria on the Corrosion Behavior of High Strength Steel EQ70 under Cathodic Polarization.

Certain species of sulfate-reducing bacteria (SRB) use cathodes as electron donors for metabolism, and this electron transfer process may influence the proper protection potential choice for structures. The interaction between SRB and polarized electrodes had been the focus of numerous investigations. In this paper, the impact of cathodic protection (CP) on Desulfovibrio caledoniens metabolic activity and its influence on highs trength steel EQ70 were studied by bacterial analyses and electrochemical measurements. The results showed that EQ70 under -0.85 VSCE CP had a higher corrosion rate than that without CP, while EQ70 with -1.05 VSCE had a lower corrosion rate. The enhanced SRB metabolic activity at -0.85 VSCE was most probably caused by the direct electron transfer from the electrode polarized at -0.85 VSCE. This direct electron transfer pathway was unavailable in -1.05 VSCE. In addition, the application of cathodic protection led to the transformation of sulfide rusts into carbonates rusts. These observations have been employed to provide updated recommendations for the optimum CP potential for steel structures in the presence of SRB.

Study of iron sulphides in long-term iron corrosion processes: Characterisations of archaeological artefacts

Iron sulphides are observed on long term anoxic corrosion profiles of iron artefacts. The archaeological nails studied came from two terrestrial sites (Glinet and Raadhuspladsen) and a subaquatic one (Arles-Rhône 3).Greigite (Fe3S4) and/or mackinawite (FeS1−x) are observed at the outer border of the corrosion product layer. The presence of mackinawite is discussed relatively to the establishment of stable anoxic burial conditions. The nails from the subaquatic site present pyrite globules in the transformed medium. The formation of pyrite (FeS2) is attributed to the proximity of wood. The iron sulphides formation may also be explained by the presence of sulphate-reducing bacteria in the burial environment.

Treatment of antimony mine drainage: challenges and opportunities with special emphasis on mineral adsorption and sulfate reducing bacteria.

The present article summarizes antimony mine distribution, antimony mine drainage generation and environmental impacts, and critically analyses the remediation approach with special emphasis on iron oxidizing bacteria and sulfate reducing bacteria. Most recent research focuses on readily available low-cost adsorbents, such as minerals, wastes, and biosorbents. It is found that iron oxides prepared by chemical methods present superior adsorption ability for Sb(III) and Sb(V). However, this process is more costly and iron oxide activity can be inhibited by plenty of sulfate in antimony mine drainage. In the presence of sulfate reducing bacteria, sulfate can be reduced to sulfide and form Sb(2)S(3) precipitates. However, dissolved oxygen and lack of nutrient source in antimony mine drainage inhibit sulfate reducing bacteria activity. Biogenetic iron oxide minerals from iron corrosion by iron-oxidizing bacteria may prove promising for antimony adsorption, while the micro-environment generated from iron corrosion by iron oxidizing bacteria may provide better growth conditions for symbiotic sulfate reducing bacteria. Finally, based on biogenetic iron oxide adsorption and sulfate reducing bacteria followed by precipitation, the paper suggests an alternative treatment for antimony mine drainage that deserves exploration.