The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
M E Abdel Sami - One of the best experts on this subject based on the ideXlab platform.
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Cultivation and Detection of Sulfate Reducing Bacteria (SRB) in Sea Water
Journal of American Science, 2011Co-Authors: E A Ghazy, Mg Mahmoud, M S Asker, M N Mahmoud, M M Abo Elsoud, M E Abdel SamiAbstract:Sulfate-Reducing Bacteria (SRB) represent a class of anaerobic microorganisms that conduct dissimulatory sulfate reduction to obtain energy. The present study aimed to detect and control SRB activities using a very rapid detectable culture medium and reduction of potential economic loss in the petroleum sector. This study is an attempt to isolate SRB from sea water by rapid and sensitive culture media and to control their effect using eight commercial biocides (Aldehydes and quaternaries). The present work studies the effect of composition of four recommended culture media (Postgate medium B, Starkey, Baar's and API media), besides, the presence of metal coupons in these media to enhance the growth of sessile SRB. Furthermore, the present study evaluates the efficiency of filtration of these culture media on the growth of SRB. The results revealed that modified Postgate medium B was the recommended medium for SRB growth. In addition, the results showed that rapid and abundant growth of SRB when the metal coupons were immersed in the culture media which were deficient in iron. The unfiltered culture media improved the SRB growth. The growth of SRB was depressed by 15 ppm of the commercial quaternaries rather than 20 ppm of the aldehydes. [E. A. Ghazy, M.G. Mahmoud, M. S. Asker, M. N. Mahmoud, M. M. Abo Elsoud and M. E. Abdel Samie. Cultivation and detection of sulfate reducing Bacteria (SRB) in sea water.
Theo A. Hansen - One of the best experts on this subject based on the ideXlab platform.
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Demethylation and cleavage of dimethylsulfoniopropionate and reduction of dimethyl sulfoxide by Sulfate-Reducing Bacteria
Geomicrobiology Journal, 1998Co-Authors: Marc J. E. C. Van Der Maarel, Michael Jansen, Henk M. Jonkers, Theo A. HansenAbstract:Many marine algae contain high concentrations of dimethylsulfoniopropionate (DMSP); most likely this compound functions mainly as an osmolyte. In anoxic marine sediments DMSP can be degraded in two ways: via an initial demethylation, or via a cleavage to dimethyl sulfide (DMS) and acrylate. Although the occurrence of these processes in sediments was known, the types of organisms responsible for them were not. Recent data from our laboratory, however, have shown that certain types of sulfate‐reducing Bacteria can carry out a demethylation of DMSP, whereas another sulfate reducer was found to cleave DMSP to DMS and acrylate, which was reduced to propionate. Thus, sulfate‐reducing Bacteria might be responsible for at least a part of the observed DMSP transformations in anoxic sediments. It was also shown that a well‐known oxidation product of DMS, dimethyl sulfoxide, can function as an alternative electron acceptor in the metabolism of some marine sulfate reducers. These data are reviewed in the present article.
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Dimethylsulfoxide reduction by marine sulfate‐reducing Bacteria
Fems Microbiology Letters, 1996Co-Authors: Henk M. Jonkers, Marc J. E. C. Van Der Maarel, Hans Van Gemerden, Theo A. HansenAbstract:Dimethylsulfoxide (DMSO) reduction occurred in five out of nine strains of Sulfate-Reducing Bacteria from marine or saline environments, but not in three freshwater isolates. DMSO reduction supported growth in all positive strains. In Desulfovibrio desulfuricans strain PA2805, DMSO reduction occurred simultaneously with sulfate reduction and was not effectively inhibited by molybdate, a specific inhibitor of sulfate reduction. The growth yield per mol lactate was 26% higher with DMSO than with sulfate as electron acceptor. In extracts of cells of strain PA2805 grown on sulfate, a low level of DMSO-reducing activity was present (0.013 μmol (mg protein)− min−); higher levels were found in cells grown on DMSO (0.56 μmol (mg protein)− min−). In anoxic marine environments DMSO reduction by Sulfate-Reducing Bacteria may lead to enhanced dimethylsulfide emission rates.
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Dimethylsulfoxide reduction by marine Sulfate-Reducing Bacteria
Fems Microbiology Letters, 1996Co-Authors: Henk M. Jonkers, Marc J. E. C. Van Der Maarel, Hans Van Gemerden, Theo A. HansenAbstract:Dimethylsulfoxide (DMSO) reduction occurred in five out of nine strains of Sulfate-Reducing Bacteria from marine or saline environments, but not in three freshwater isolates. DMSO reduction supported growth in all positive strains. In Desulfovibrio desulfuricans strain PA2805, DMSO reduction occurred simultaneously with sulfate reduction and was not effectively inhibited by molybdate, a specific inhibitor of sulfate reduction. The growth yield per mol lactate was 26% higher with DMSO than with sulfate as electron acceptor. In extracts of cells of strain PA2805 grown on sulfate, a low level of DMSO-reducing activity was present (0.013 μmol (mg protein)− min−); higher levels were found in cells grown on DMSO (0.56 μmol (mg protein)− min−). In anoxic marine environments DMSO reduction by Sulfate-Reducing Bacteria may lead to enhanced dimethylsulfide emission rates.
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Carbon Metabolism of Sulfate-Reducing Bacteria
Brock Springer Series in Contemporary Bioscience, 1993Co-Authors: Theo A. HansenAbstract:In the nearly 100 years that Sulfate-Reducing Bacteria have been studied in pure, or supposedly pure, cultures, our ideas about their carbon metabolism have gone through periods of sometimes slow but occasionally drastic changes. In the past 20 years it has become clear that (1) far more compounds can be oxidized by sulfate reducers than previously thought; (2) organic compounds can be oxidized completely, beyond the level of acetate, to CO2; and (3) some Sulfate-Reducing Bacteria have the potential for fully autotrophic growth. Furthermore, the awareness has grown that a detailed knowledge of their carbon metabolism is required for a proper understanding of the bioenergetic aspects of sulfate reduction and of their role in nature.
E A Ghazy - One of the best experts on this subject based on the ideXlab platform.
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Cultivation and Detection of Sulfate Reducing Bacteria (SRB) in Sea Water
Journal of American Science, 2011Co-Authors: E A Ghazy, Mg Mahmoud, M S Asker, M N Mahmoud, M M Abo Elsoud, M E Abdel SamiAbstract:Sulfate-Reducing Bacteria (SRB) represent a class of anaerobic microorganisms that conduct dissimulatory sulfate reduction to obtain energy. The present study aimed to detect and control SRB activities using a very rapid detectable culture medium and reduction of potential economic loss in the petroleum sector. This study is an attempt to isolate SRB from sea water by rapid and sensitive culture media and to control their effect using eight commercial biocides (Aldehydes and quaternaries). The present work studies the effect of composition of four recommended culture media (Postgate medium B, Starkey, Baar's and API media), besides, the presence of metal coupons in these media to enhance the growth of sessile SRB. Furthermore, the present study evaluates the efficiency of filtration of these culture media on the growth of SRB. The results revealed that modified Postgate medium B was the recommended medium for SRB growth. In addition, the results showed that rapid and abundant growth of SRB when the metal coupons were immersed in the culture media which were deficient in iron. The unfiltered culture media improved the SRB growth. The growth of SRB was depressed by 15 ppm of the commercial quaternaries rather than 20 ppm of the aldehydes. [E. A. Ghazy, M.G. Mahmoud, M. S. Asker, M. N. Mahmoud, M. M. Abo Elsoud and M. E. Abdel Samie. Cultivation and detection of sulfate reducing Bacteria (SRB) in sea water.
Manuel J T Carrondo - One of the best experts on this subject based on the ideXlab platform.
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Effect of hydrogen sulfide on growth of sulfate reducing Bacteria
Biotechnology and Bioengineering, 1992Co-Authors: M A M Reis, J. S. Almeida, P. C. Lemos, Manuel J T CarrondoAbstract:A culture of sulfate reducing Bacteria (SRB) growing on lactate and sulfate was incubated at different pH values in the range of 5.8-7.0. The effect of pH on growth rate was determined in this pH range; the highest growth rate was observed at pH 6.7. Hydrogen sulfide produced from sulfate reduction was found to have a direct and reversible toxicity effect on the SRB. A hydrogen sulfide Concentration of 547 mg/L (16.1 mM) completely inhibited the culture growth. Comparison between acetic acid and hydrogen sulfide inhibition is presented and the concomitant inhibition kinetics are mathematically described.
M M Abo Elsoud - One of the best experts on this subject based on the ideXlab platform.
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Cultivation and Detection of Sulfate Reducing Bacteria (SRB) in Sea Water
Journal of American Science, 2011Co-Authors: E A Ghazy, Mg Mahmoud, M S Asker, M N Mahmoud, M M Abo Elsoud, M E Abdel SamiAbstract:Sulfate-Reducing Bacteria (SRB) represent a class of anaerobic microorganisms that conduct dissimulatory sulfate reduction to obtain energy. The present study aimed to detect and control SRB activities using a very rapid detectable culture medium and reduction of potential economic loss in the petroleum sector. This study is an attempt to isolate SRB from sea water by rapid and sensitive culture media and to control their effect using eight commercial biocides (Aldehydes and quaternaries). The present work studies the effect of composition of four recommended culture media (Postgate medium B, Starkey, Baar's and API media), besides, the presence of metal coupons in these media to enhance the growth of sessile SRB. Furthermore, the present study evaluates the efficiency of filtration of these culture media on the growth of SRB. The results revealed that modified Postgate medium B was the recommended medium for SRB growth. In addition, the results showed that rapid and abundant growth of SRB when the metal coupons were immersed in the culture media which were deficient in iron. The unfiltered culture media improved the SRB growth. The growth of SRB was depressed by 15 ppm of the commercial quaternaries rather than 20 ppm of the aldehydes. [E. A. Ghazy, M.G. Mahmoud, M. S. Asker, M. N. Mahmoud, M. M. Abo Elsoud and M. E. Abdel Samie. Cultivation and detection of sulfate reducing Bacteria (SRB) in sea water.
