Ferric iron reduction by Thiobacillus ferrooxidans at extremely low pH-values

1989 ◽  
Vol 7 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Woflfgang Sand
Keyword(s):  
Iron Reduction ◽  
Ferric Iron ◽  
Thiobacillus Ferrooxidans ◽  
Low Ph ◽  
Ph Values

Enrichment and isolation of acid-tolerant sulfate-reducing microorganisms in the anoxic, acidic hot spring sediments from Copahue volcano, Argentina

2019 ◽  
Vol 95 (12) ◽  
Author(s):  
Graciana Willis ◽  
Ivan Nancucheo ◽  
Sabrina Hedrich ◽  
Alejandra Giaveno ◽  
Edgardo Donati ◽  
...  
Keyword(s):  
Ferric Iron ◽  
Hot Spring ◽  
Low Ph ◽  
Acidophilic Microorganisms ◽  
Sulfate Reducing ◽  
Ph Values ◽  
Organic Electron ◽  
Acid Tolerant ◽  
Biotechnological Processes ◽  
Iron Precipitates

ABSTRACT The geothermal Copahue-Caviahue (GCC) system (Argentina) is an extreme acidic environment, dominated by the activity of Copahue volcano. Environments characterised by low pH values, such as volcanic areas, are of particular interest for the search of acidophilic microorganisms with application in biotechnological processes. In this work, sulfate-reducing microorganisms were investigated in geothermal acidic, anaerobic zones from GCC system. Sediment samples from Agua del Limón (AL1), Las Máquinas (LMa2), Las Maquinitas (LMi) and Baño 9 (B9–2, B9–3) were found to be acidic (pH values 2.1–3.0) to moderate acidic (5.1–5.2), containing small total organic carbon values, and ferric iron precipitates. The organic electron donor added to the enrichment was completely oxidised to CO2. Bacteria related to ‘Desulfobacillus acidavidus’ strain CL4 were found to be dominant (67–83% of the total number of clones) in the enrichment cultures, and their presence was confirmed by their isolation on overlay plates. Other bacteria were also detected with lower abundance (6–20% of the total number of clones), with representatives of the genera Acidithiobacillus, Sulfobacillus, Alicyclobacillus and Athalassotoga/Mesoaciditoga. These enrichment and isolates found at low pH confirm the presence of anaerobic activities in the acidic sediments from the geothermal Copahue-Caviahue system.

THE OCCURENCE OF BASIC FERRIC SULFATES IN SOME CANADIAN SOILS

1981 ◽  
Vol 61 (1) ◽  
pp. 99-107 ◽  
Author(s):  
G.J. ROSS ◽  
K.C. IVARSON
Keyword(s):  
Construction Projects ◽  
Thiobacillus Ferrooxidans ◽  
Low Ph ◽  
Acid Sulfate ◽  
Ph Values ◽  
Canadian Soils ◽  
Arctic Area

Acid sulfate conditions were found in six soils from various areas in Canada by the presence of basic ferric sulfates, the prominence of the iron oxidizing bacterium Thiobacillus ferrooxidans, and the low pH values from 2.9 to 4.2. The content of natrojarosite [NaFe3(SO4)2(OH)6] was greater than, or equal to, jarosite [KFe3(SO4)2(OH)6] in the majority of the soils. The Boundary, Keld and Nicomekl soils from western areas and the Kanguk soil from an arctic area contained relatively large proportions of natrojarosite whereas the de l’Anse and Acadia soils contained larger proportions of jarosite. The recognition of acid sulfate conditions in soils and underlying materials is important not only in relation to agriculture but also with respect to construction projects, as strong acidification and corrosion may be expected, even in permafrost areas, upon exposure of pyrite-containing shales to air.

Development of a Strategy for Selective Metal Recovery from Pregnant Leach Solutions of Kupferschiefer Bioleaching

2015 ◽  
Vol 1130 ◽  
pp. 255-258 ◽  
Author(s):  
Sabrina Hedrich ◽  
Axel Schippers ◽  
D. Barrie Johnson
Keyword(s):  
Ferric Iron ◽  
Low Ph ◽  
Metal Recovery ◽  
Novel Technique ◽  
Ph Values ◽  
Sulfate Removal ◽  
Iron Copper ◽  
Valuable Metals ◽  
Copper Zinc ◽  
High Concentrations

Pregnant leach solutions (PLS) resulting from bioleaching of copper concentrate from Kupferschiefer are characterized by low pH values and high concentrations of mainly ferric iron, copper, zinc and sulfate, as well as significant amounts of nickel and cobalt. In order to recover the valuable metals for further processing, a novel technique that promotes selective metal recovery and sulfate removal from acidic liquors, described in this study, is proposed.

scholarly journals Adaptation of Lactobacillus plantarum IMDO 130201, a Wheat Sourdough Isolate, to Growth in Wheat Sourdough Simulation Medium at Different pH Values through Differential Gene Expression

2011 ◽  
Vol 77 (10) ◽  
pp. 3406-3412 ◽  
Author(s):  
Gino Vrancken ◽  
Luc De Vuyst ◽  
Tom Rimaux ◽  
Joke Allemeersch ◽  
Stefan Weckx
Keyword(s):  
Gene Expression ◽  
Lactobacillus Plantarum ◽  
Differential Gene Expression ◽  
Lipoteichoic Acid ◽  
Low Ph ◽  
Exponential Growth Phase ◽  
Cellular Mechanisms ◽  
Content Type ◽  
Ph Values ◽  
Differential Gene

ABSTRACTSourdough is a very competitive and challenging environment for microorganisms. Usually, a stable microbiota composed of lactic acid bacteria (LAB) and yeasts dominates this ecosystem. Although sourdough is rich in carbohydrates, thus providing an ideal environment for microorganisms to grow, its low pH presents a particular challenge. The nature of the adaptation to this low pH was investigated forLactobacillus plantarumIMDO 130201, an isolate from a laboratory wheat sourdough fermentation. Batch fermentations were carried out in wheat sourdough simulation medium, and total RNA was isolated from mid-exponential-growth-phase cultures, followed by differential gene expression analysis using a LAB functional gene microarray. At low pH values, an increased expression of genes involved in peptide and amino acid metabolism was found as well as that of genes involved in plantaricin production and lipoteichoic acid biosynthesis. The results highlight cellular mechanisms that allowL. plantarumto function at a low environmental pH.

scholarly journals Mechanism of Coagulation of Humic Acid in Presence of Metal Ion Coagulants at Low pH Values

1970 ◽  
Vol 73 (5) ◽  
pp. 874-878 ◽  
Author(s):  
Takao YOTSUYANAGI ◽  
Katsumi GOTO ◽  
Masaichi NAGAYAMA
Keyword(s):  
Humic Acid ◽  
Metal Ion ◽  
Low Ph ◽  
Ph Values

scholarly journals Histidine-Rich Glycoprotein Inhibits HIV-1 Infection in a pH-Dependent Manner

2018 ◽  
Vol 93 (4) ◽  
Author(s):  
Ezequiel Dantas ◽  
Fernando Erra Díaz ◽  
Pehuén Pereyra Gerber ◽  
Augusto Varese ◽  
Diana Alicia Jerusalinsky ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Respiratory Syncytial Virus ◽  
Herpes Simplex ◽  
Low Ph ◽  
Vaginal Mucosa ◽  
Ph Values ◽  
Syncytial Virus ◽  
Simplex Virus ◽  
Herpes Simplex Virus 2 ◽  
Hiv 1

ABSTRACTHistidine-rich glycoprotein (HRG) is an abundant plasma protein with a multidomain structure, allowing its interaction with many ligands, including phospholipids, plasminogen, fibrinogen, IgG antibodies, and heparan sulfate. HRG has been shown to regulate different biological responses, such as angiogenesis, coagulation, and fibrinolysis. Here, we found that HRG almost completely abrogated the infection of Ghost cells, Jurkat cells, CD4+T cells, and macrophages by HIV-1 at a low pH (range, 6.5 to 5.5) but not at a neutral pH. HRG was shown to interact with the heparan sulfate expressed by target cells, inhibiting an early postbinding step associated with HIV-1 infection. More importantly, by acting on the viral particle itself, HRG induced a deleterious effect, which reduces viral infectivity. Because cervicovaginal secretions in healthy women show low pH values, even after semen deposition, our observations suggest that HRG might represent a constitutive defense mechanism in the vaginal mucosa. Of note, low pH also enabled HRG to inhibit the infection of HEp-2 cells and Vero cells by respiratory syncytial virus (RSV) and herpes simplex virus 2 (HSV-2), respectively, suggesting that HRG might display broad antiviral activity under acidic conditions.IMPORTANCEVaginal intercourse represents a high-risk route for HIV-1 transmission. The efficiency of male-to-female HIV-1 transmission has been estimated to be 1 in every 1,000 episodes of sexual intercourse, reflecting the high degree of protection conferred by the genital mucosa. However, the contribution of different host factors to the protection against HIV-1 at mucosal surfaces remains poorly defined. Here, we report for the first time that acidic values of pH enable the plasma protein histidine-rich glycoprotein (HRG) to strongly inhibit HIV-1 infection. Because cervicovaginal secretions usually show low pH values, our observations suggest that HRG might represent a constitutive antiviral mechanism in the vaginal mucosa. Interestingly, infection by other viruses, such as respiratory syncytial virus and herpes simplex virus 2, was also markedly inhibited by HRG at low pH values, suggesting that extracellular acidosis enables HRG to display broad antiviral activity.

scholarly journals Effect of water temperature and pH on the concentration and time of ozone saturation

2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Melicia Cintia Galdeano ◽  
Allan Eduardo Wilhelm ◽  
Isabella Borges Goulart ◽  
Renata Valeriano Tonon ◽  
Otniel Freitas-Silva ◽  
...  
Keyword(s):  
Water Temperature ◽  
Molecular Oxygen ◽  
Half Life ◽  
Low Ph ◽  
Ozone Content ◽  
Effect Of Temperature ◽  
Saturation Time ◽  
Gas Concentration ◽  
Ph Values ◽  
Effect Of Water

Abstract Ozone has been used for many years to disinfect water due to its oxidizing potential. Since it decomposes quickly into molecular oxygen, leaving no residue, it has important advantages for use. The decomposition of ozone is affected by the temperature and pH of the medium, low pH values and temperatures increasing its half-life, which can result in more efficient disinfection. With the objective of increasing the effectiveness of ozonation, this study investigated the effect of temperature (8 ºC and 25 °C) and pH (3.0 and 6.0) of the water on the saturation time and gas concentration, employing two initial gas concentrations (13.3 and 22.3 mg L-1). The concentration of ozone saturation increased as the temperature and pH of the medium decreased, as also with the higher initial gas concentration ( C0). The highest saturation concentrations were obtained at pH 3.0 and 8 °C (4.50 and 8.03 mg L-1 with C0 of 13.3 and 22.3 mg L-1, respectively). This higher ozone content could result in greater decontamination efficiency of the food products washed with this water.

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