scholarly journals Composition and Corrosivity of Extracellular Polymeric Substances from The Hydrocarbon-Degrading Sulfate-Reducing Bacterium Desulfoglaeba alkanexedens ALDC

2021 ◽  
Vol 9 (9) ◽  
pp. 1994
Author(s):  
Irene A. Davidova ◽  
Tiffany R. Lenhart ◽  
Mark A. Nanny ◽  
Joseph M. Suflita
Keyword(s):  
Chemical Composition ◽  
Extracellular Polymeric Substances ◽  
Fluorescent Microscopy ◽  
Ring Structure ◽  
Resonance Spectroscopy ◽  
Pyranose Ring ◽  
Sulfate Reducing ◽  
Degrading Bacterium ◽  
Hydrocarbon Substrates ◽  
Reducing Bacteria

Sulfate-reducing bacteria (SRB) often exist as cell aggregates and in biofilms surrounded by a matrix of extracellular polymeric substances (EPSs). The chemical composition of EPSs may facilitate hydrophobic substrate biodegradation and promote microbial influenced corrosion (MIC). Although EPSs from non-hydrocarbon-degrading SRB have been studied; the chemical composition of EPSs from hydrocarbon-degrading SRBs has not been reported. The isolated EPSs from the sulfate-reducing alkane-degrading bacterium Desulfoglaeba alkanexedens ALDC was characterized with scanning and fluorescent microscopy, nuclear magnetic resonance spectroscopy (NMR), and by colorimetric chemical assays. Specific fluorescent staining and 1H NMR spectroscopy revealed that the fundamental chemical structure of the EPS produced by D. alkanexedens is composed of pyranose polysaccharide and cyclopentanone in a 2:1 ratio. NMR analyses indicated that the pyranose ring structure is bonded by 1,4 connections with the cyclopentanone directly bonded to one pyranose ring. The presence of cyclopentanone presumably increases the hydrophobicity of the EPS that may facilitate the accessibility of hydrocarbon substrates to aggregating cells or cells in a biofilm. Weight loss and iron dissolution experiments demonstrated that the EPS did not contribute to the corrosivity of D. alkanexedens cells.

scholarly journals Can Primary Ferroan Dolomite and Ankerite Be Precipitated? Its Implications for Formation of Submarine Methane-Derived Authigenic Carbonate (MDAC) Chimney

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 413 ◽  
Author(s):  
Fan Xu ◽  
Xuelian You ◽  
Qing Li ◽  
Yi Liu
Keyword(s):  
Iron Reduction ◽  
Extracellular Polymeric Substances ◽  
Microbial Culture ◽  
Reduction Zone ◽  
Secondary Products ◽  
Iron Reducing Bacteria ◽  
Sulfate Reducing ◽  
Dolomite Problem ◽  
Reducing Bacteria ◽  
Ferroan Dolomite

Microbes can mediate the precipitation of primary dolomite under surface conditions. Meanwhile, primary dolomite mediated by microbes often contains more Fe2+ than standard dolomite in modern microbial culture experiments. Ferroan dolomite and ankerite have been regarded as secondary products. This paper reviews the process and possible mechanisms of microbial mediated precipitation of primary ferroan dolomite and/or ankerite. In the microbial geochemical Fe cycle, many dissimilatory iron-reducing bacteria (DIRB), sulfate-reducing bacteria (SRB), and methanogens can reduce Fe3+ to Fe2+, while SRB and methanogens can also promote the precipitation of primary dolomite. There are an oxygen respiration zone (ORZ), an iron reduction zone (IRZ), a sulfate reduction zone (SRZ), and a methanogenesis zone (MZ) from top to bottom in the muddy sediment diagenesis zone. DIRB in IRZ provide the lower section with Fe2+, which composes many enzymes and proteins to participate in metabolic processes of SRB and methanogens. Lastly, heterogeneous nucleation of ferroan dolomite on extracellular polymeric substances (EPS) and cell surfaces is mediated by SRB and methanogens. Exploring the origin of microbial ferroan dolomite may help to solve the “dolomite problem”.

Phylogenetic Analysis and Microbiologically Influenced Corrosion of a Kind of Sulfate-Reducing Bacteria

2011 ◽  
Vol 199-200 ◽  
pp. 102-105
Author(s):  
Xiao Dong Zhao ◽  
Jie Yang ◽  
Xi Qiu Fan
Keyword(s):  
Electron Microscopy ◽  
Phylogenetic Analysis ◽  
Marine Environment ◽  
Fluorescent Microscopy ◽  
Sulfate Reducing Bacteria ◽  
Microbiologically Influenced Corrosion ◽  
Sulfate Reducing ◽  
Transmission Electron ◽  
Reducing Bacteria

A kind of sulfate-reducing bacteria was isolated from the actual marine environment, cultured and enriched for phylogenetic analysis by molecular biology methods, and observed under fluorescent microscopy and transmission electron microscopy to determine the species and morphology. Taking the bacteria as the main object, the influenced corrosion behavior of steels in marine environment was studied in follow-up experiments.

scholarly journals The Technology of Producing Biohumus and the Study of its Qualitative Indicators

2021 ◽  
Author(s):  
Anna Gneush ◽  
Inna Zholobova ◽  
Alexander Petenko ◽  
Natalia Gorkovenko ◽  
Natalia Yurina
Keyword(s):  
Chemical Composition ◽  
Organic Fertilizer ◽  
Fulvic Acids ◽  
Microbiological Analysis ◽  
Sulfate Reducing ◽  
Physiological Group ◽  
Number Of Microorganisms ◽  
Total Composition ◽  
Reducing Bacteria ◽  
Microbiological Analyses

This article presents the results from the development of a technology for producing biohumus from the feces of cattle and winter wheat straw in a biodynamic fermenter. Nitrifying agents are important for soil fertility, which is dependent on the intensity of the nitrification process. This group includes aerobic cellulose-destroying microorganisms, denitrifiers and sulfate-reducing bacteria. The ratio of these groups and their composition are changing. Therefore, the study of the quantitative ratio of microbial communities involved in the formation of biohumus was of considerable scientific interest. During the microbiological analyses, a large number of microorganisms were found to be involved in the decomposition of the organic compounds. Aminoautotrophic microorganisms represented the largest physiological group of microorganisms in the biohumus. The chemical composition of the biohumus was determined during the study and a sanitary microbiological analysis was performed. The content of gross forms of elements in the humic extract was also examined. The humic extract from the biohumus was a brown liquid with 15 g / l of humic acids, 5.0 g / l of fulvic acids, and gross forms of elements (potassium, phosphorus, nitrogen). The dry matter in the biohumus was 1.0% of the total composition and contained 0.1% nitrogen, 0.03% phosphorus P2O5 and 0.01% potassium K2O. It was found that high-quality organic fertilizer can be obtained using this technology. Keywords: biohumus, humic extract, chemical composition, sanitary-microbiological analysis, organic fertilizer

Using laboratory investigations to reveal the palaeohydrological implications of aragonite laminae deposition in the endorheic Dead Sea and its precursors under different climatic conditions

2021 ◽  
Author(s):  
Yoav Ben Dor ◽  
Tomer Flax ◽  
Itamar Levitan ◽  
Achim Brauer ◽  
Yehouda Enzel ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Extracellular Polymeric Substances ◽  
Dead Sea ◽  
Climatic Conditions ◽  
Carbonate Production ◽  
Sulfate Reducing ◽  
The Dead ◽  
Environmental Archive ◽  
Summer Time ◽  
Reducing Bacteria

<p>The sedimentary record of the endorheic Dead Sea and its precursors comprises aragonite laminae that make up an environmental archive extending into the Pleistocene, partially in annual resolution. Nevertheless, despite the importance of resolving the conditions that facilitate aragonite precipitation in the Dead Sea, contradictions exist between recent studies that utilized modern observations and the late Pleistocene geological record. The implications of aragonite precipitation in the Dead Sea and in its late Pleistocene predecessor Lake Lisan were investigated in this study by mixing natural and synthetic brines with a synthetic bicarbonate solution representing flood water entering the lake (4mM), with and without additions of extracellular polymeric substances (EPS). This was followed by measurements of aragonite precipitation incubation, rates, yields. Aragonite precipitation took place within days to few weeks after mixing of the brine with the synthetic bicarbonate solution and its incubation time was proportional to bicarbonate concentrations, while precipitation rates were also influenced by ionic strength. The addition of EPS inhibited aragonite precipitation for several months, which provides a reasonable explanation for the proposed summer-time precipitation of aragonite during the late Pleistocene glacials. We suggest that under increased inflow, increased biological activity would result in increased EPS production that could inhibit aragonite precipitation for several months. Finally, previous estimates of the freshwater inflow required to provide the carbonate for a uniform aragonite lamina of a typical thickness deposited during glacials are unreasonably high. This can be resolved by various processes: (1) Patchy aragonite deposition over limited segments of the lake’s floor; (2) Supply of additional carbonate to the lake from aeolian dust and recycled dust deposits; (3) Carbonate production through the oxidation of organic carbon by sulfate-reducing bacteria at the hypolimnion. Altogether, these results indicate that aragonite laminae thicknesses are insufficient to quantitatively reconstruct the hydrological balance for the entire lake, but may still be valuable for identifying climatic periodicities over a continuous record in a specific study site.</p>

Influence and Mechanism of Cu2+ on Removal of U(VI) by Sulfate Reducing Bacteria

2011 ◽  
Vol 236-238 ◽  
pp. 903-908 ◽  
Author(s):  
Yue Lin Liu ◽  
Shui Bo Xie ◽  
Hui Ling ◽  
Wen Tao Wang ◽  
Shi You Li ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Lactic Acid ◽  
Extracellular Polymeric Substances ◽  
Adsorption Process ◽  
Reduction Process ◽  
Sulfate Reducing Bacteria ◽  
Main Process ◽  
Total Removal ◽  
Sulfate Reducing ◽  
Reducing Bacteria

In order to research on the inhibition of Cu2+to removal of U(Ⅵ) by sulfate reducing bacteria(SRB), the experiment investigated the removal of U(Ⅵ) by SRB through H2S reduction process, elecrton transfer process and adsorption process respectively. The results showed that the electron transfer was the main process in removing of U(Ⅵ) by SRB, It accounted for 80% of the total removal. Extracellular polymeric substances (EPS) adsorption of U(Ⅵ) had little effect. When the concentration of Cu2+was 5mg/L, Cu2+had little effect on the removal U(Ⅵ) by SRB; It inhibited the removal of U(Ⅵ) significantly when the concentration was 15mg/L because of the competition of H2S and the electronics of lactic acid between Cu2+and U(Ⅵ); When the concentration of Cu2+exceeded 25mg/L, it would damage the integrity of SRB’s membrane and the removal of U(Ⅵ) was completely inhibited.

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