scholarly journals Medium Preparation for the Cultivation of Microorganisms under Strictly Anaerobic/Anoxic Conditions

Author(s):  
Andreas O. Wagner ◽  
Rudolf Markt ◽  
Mira Mutschlechner ◽  
Nina Lackner ◽  
Eva M. Prem ◽  
...  

Microbiology ◽  
2003 ◽  
Vol 149 (6) ◽  
pp. 1513-1522 ◽  
Author(s):  
Paula Fareleira ◽  
Bruno S. Santos ◽  
Célia António ◽  
Pedro Moradas-Ferreira ◽  
Jean LeGall ◽  
...  

The biochemical response to oxygen of the strictly anaerobic sulfate-reducing bacterium Desulfovibrio gigas was studied with the goal of elucidating survival strategies in oxic environments. Cultures of D. gigas on medium containing lactate and sulfate were exposed to oxygen (concentration 5–120 μM). Growth was fully inhibited by oxygen, but the cultures resumed growth as soon as they were shifted back to anoxic conditions. Following 24 h exposure to oxygen the growth rate was as high as 70 % of the growth rates observed before oxygenation. Catalase levels and activity were enhanced by exposure to oxygen whereas superoxide-scavenging and glutathione reductase activities were not affected. The general pattern of cellular proteins as analysed by two-dimensional electrophoresis was altered in the presence of oxygen, the levels of approximately 12 % of the detected proteins being markedly increased. Among the induced proteins, a homologue of a 60 kDa eukaryotic heat-shock protein (Hsp60) was identified by immunoassay analysis. In the absence of external substrates, the steady-state levels of nucleoside triphosphates detected by in vivo 31P-NMR under saturating concentrations of oxygen were 20 % higher than under anoxic conditions. The higher energy levels developed under oxygen correlated with a lower rate of substrate (glycogen) mobilization, but no experimental evidence for a contribution from oxidative phosphorylation was found. The hypothesis that oxygen interferes with ATP dissipation processes is discussed.



1996 ◽  
Vol 34 (10) ◽  
pp. 25-33 ◽  
Author(s):  
Cheng Jiayang ◽  
Makram T. Suidan ◽  
Albert D. Venosa

Abiotic reduction of 2,4-dinitrotoluene (DNT) in the presence of sulfide minerals has been investigated under anoxic conditions at 35°C. 2,4-DNT was abiotically reduced to 4-amino-2-nitrotoluene (4-A-2-NT) and 2-amino-4-nitrotoluene (2-A-4-NT) in the presence of high concentration of sulfide (0.84 mM). No abiotic reduction of 2,4-DNT was observed in the presence of low sulfide concentration (0.42 mM). The rate and the extent of the abiotic reduction of 2,4-DNT were increased with an increase in sulfide concentration. Sulfide served as an electron donor for the reduction of 2,4-DNT. The 2-nitro group was preferentially reduced, making the 2-A-4-NT:4-A-2-NT ratio in the final products 2:1. The addition of iron, nickel, and cobalt minerals significantly enhanced the abiotic reduction. The FeS, NiS, and CoS solids formed in the serum bottles catalyzed the reduction of 2,4-DNT preferentially to 4-A-2-NT. MnS and CuS solids also catalyzed the reduction of 2,4-DNT to 4-A-2-NT, but did not change the overall reduction of 2,4-DNT. However, the presence of calcium, zinc, and magnesium minerals impeded 2,4-DNT reduction. The calcium, zinc, and magnesium ions have a high affinity to sulfide, inactivating sulfide as an electron donor for the chemical reduction of 2,4-DNT.



1996 ◽  
Vol 34 (5-6) ◽  
pp. 67-74 ◽  
Author(s):  
D. Orhon ◽  
S. Sözen ◽  
N. Artan

For single-sludge denitrification systems, modelling of anoxic reactors currently uses the kinetics of aerobic heterotrophic growth together with a correction factor for anoxic conditions. This coefficient is computed on the basis of respirometric measurements with the assumption that the heterotrophic yield remains the same under aerobic and anoxic coditions. The paper provides the conceptual proof that the yield coefficient is significantly lower for the anoxic growth on the basis of the energetics of the related metabolic processes. This is used for the interpretation of the very high values for the correction factor experimentally determined for a number of industrial wastewaters. A default value for the anoxic heterotrophic yield coefficient is calculated for domestic sewage and compatible wastewaters and proposed for similar evaluations.



Author(s):  
Florian P. Rosenbaum ◽  
Anja Poehlein ◽  
Richard Egelkamp ◽  
Rolf Daniel ◽  
Sönke Harder ◽  
...  


Author(s):  
Hussain Aqeel ◽  
Mahendran Basuvaraj ◽  
Steven N. Liss

BNR granules rich in amyloid adhesins and denitrifying bacteria were formed in the SBRs that were operated with extended anoxic conditions.



Author(s):  
Fabian Gräßle ◽  
Caroline Plugge ◽  
Paolo Franchini ◽  
Bernhard Schink ◽  
David Schleheck ◽  
...  


Gut Microbes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 1-16
Author(s):  
Patrick Denis Browne ◽  
Frederik Cold ◽  
Andreas Munk Petersen ◽  
Sofie Ingdam Halkjær ◽  
Alice Højer Christensen ◽  
...  


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2491
Author(s):  
Elena Garcia ◽  
Julio Torres ◽  
Nuria Rebolledo ◽  
Raul Arrabal ◽  
Javier Sanchez

The number of reinforced concrete structures subject to anoxic conditions such as offshore platforms and geological storage facilities is growing steadily. This study explored the behaviour of embedded steel reinforcement corrosion under anoxic conditions in the presence of different chloride concentrations. Corrosion rate values were obtained by three electrochemical techniques: Linear polarization resistance, electrochemical impedance spectroscopy, and chronopotenciometry. The corrosion rate ceiling observed was 0.98 µA/cm2, irrespective of the chloride content in the concrete. By means of an Evans diagram, it was possible to estimate the value of the cathodic Tafel constant (bc) to be 180 mV dec−1, and the current limit yielded an ilim value of 0.98 µA/cm2. On the other hand, the corrosion potential would lie most likely in the −900 mVAg/AgCl to −1000 mVAg/AgCl range, whilst the bounds for the most probable corrosion rate were 0.61 µA/cm2 to 0.22 µA/cm2. The experiments conducted revealed clear evidence of corrosion-induced pitting that will be assessed in subsequent research.



2004 ◽  
Vol 50 (5) ◽  
pp. 261-268 ◽  
Author(s):  
S. Schittko ◽  
A. Putschew ◽  
M. Jekel

After bank filtration, effluent influenced surface waters are often used as raw drinking water. It is known that high concentrations of iodinated X-ray contrast media are detectable in such surface waters and thus, more knowledge about the behaviour of the contrast media during bank filtration is necessary and the subject of investigations in this study. The adsorbable organic iodine (AOI), four widely used iodinated X-ray contrast media and four possible transformation products were quantified in an influenced lake, five groundwater wells and a drinking water well. Under anoxic conditions the AOI as well as the concentration of the contrast media are decreased by bank filtration, whereby the AOI is decreased by 64% and the contrast media concentration can be reduced up to 95%, depending on the compound. In the raw drinking water the following average concentrations were determined: Iopromid <20 ng/L, Diatrizote 166 ng/L, Iopamidol 166 ng/L and Iohexol 34 ng/L. Instationary conditions during the sampling period indicate that, at least under anoxic conditions, a large part of the contrast media and transformation products, which are still iodinated, may be associated to colloids and/or humic material.



2009 ◽  
Vol 70 (3) ◽  
pp. 575-585 ◽  
Author(s):  
Sander A.B. Weelink ◽  
Wim van Doesburg ◽  
Flávia Talarico Saia ◽  
W. Irene C. Rijpstra ◽  
Wilfred F.M. Röling ◽  
...  


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