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The role of acetogens in microbially influenced corrosion of steel.

Mand J, Park HS, Jack TR, Voordouw G - Front Microbiol (2014)

Bottom Line: Through a mechanism, that is still poorly understood, electrons or hydrogen (H2) molecules are removed from the metal surface and used as electron donor for sulfate reduction.The resulting ferrous ions precipitate in part with the sulfide produced, forming characteristic black iron sulfide.An extended MIC model capturing these results is presented.

View Article: PubMed Central - PubMed

Affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada.

ABSTRACT
Microbially influenced corrosion (MIC) of iron (Fe(0)) by sulfate-reducing bacteria (SRB) has been studied extensively. Through a mechanism, that is still poorly understood, electrons or hydrogen (H2) molecules are removed from the metal surface and used as electron donor for sulfate reduction. The resulting ferrous ions precipitate in part with the sulfide produced, forming characteristic black iron sulfide. Hydrogenotrophic methanogens can also contribute to MIC. Incubation of pipeline water samples, containing bicarbonate and some sulfate, in serum bottles with steel coupons and a headspace of 10% (vol/vol) CO2 and 90% N2, indicated formation of acetate and methane. Incubation of these samples in serum bottles, containing medium with coupons and bicarbonate but no sulfate, also indicated that formation of acetate preceded the formation of methane. Microbial community analyses of these enrichments indicated the presence of Acetobacterium, as well as of hydrogenotrophic and acetotrophic methanogens. The formation of acetate by homoacetogens, such as Acetobacterium woodii from H2 (or Fe(0)) and CO2, is potentially important, because acetate is a required carbon source for many SRB growing with H2 and sulfate. A consortium of the SRB Desulfovibrio vulgaris Hildenborough and A. woodii was able to grow in defined medium with H2, CO2, and sulfate, because A. woodii provides the acetate, needed by D. vulgaris under these conditions. Likewise, general corrosion rates of metal coupons incubated with D. vulgaris in the presence of acetate or in the presence of A. woodii were higher than in the absence of acetate or A. woodii, respectively. An extended MIC model capturing these results is presented.

No MeSH data available.


Related in: MedlinePlus

Hydrogenotrophic microorganisms potentially contributing to MIC. Note that the acetate formed by acetogenic bacteria can be used as a carbon source by the SRB. Although the uptake of dihydrogen (H2) is suggested here, direct uptake of electrons from the steel surface by SRB and methanogens has also been suggested (Dinh et al., 2004; Enning et al., 2012).
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Figure 9: Hydrogenotrophic microorganisms potentially contributing to MIC. Note that the acetate formed by acetogenic bacteria can be used as a carbon source by the SRB. Although the uptake of dihydrogen (H2) is suggested here, direct uptake of electrons from the steel surface by SRB and methanogens has also been suggested (Dinh et al., 2004; Enning et al., 2012).

Mentions: These features are captured in the extended MIC model shown in Figure 9. We have shown the uptake of reducing equivalents (H+ + eāˆ’) as dihydrogen (H2), realizing that direct uptake of electrons is another mechanism that has been proposed (Dinh et al., 2004; Enning et al., 2012). Accordingly, hydrogenotrophic acetogens, methanogens, or SRB could all contribute directly to corrosion by using metallic iron as an electron donor. The combined action of hydrogenotrophic acetogens and acetotrophic methanogens would be the same as that of hydrogenotrophic methanogens alone. In the coupon-attached biofilms for P0866, P0866S, and P0848S, the hydrogenotrophic Methanobacteriaceae predominated (Table 2: 71.75ā€“89.31%), whereas the PW7 biofilm had a high fraction of Acetobacterium (2.93%) and of the acetotrophic Methanosaeta (17.14%).


The role of acetogens in microbially influenced corrosion of steel.

Mand J, Park HS, Jack TR, Voordouw G - Front Microbiol (2014)

Hydrogenotrophic microorganisms potentially contributing to MIC. Note that the acetate formed by acetogenic bacteria can be used as a carbon source by the SRB. Although the uptake of dihydrogen (H2) is suggested here, direct uptake of electrons from the steel surface by SRB and methanogens has also been suggested (Dinh et al., 2004; Enning et al., 2012).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043135&req=5

Figure 9: Hydrogenotrophic microorganisms potentially contributing to MIC. Note that the acetate formed by acetogenic bacteria can be used as a carbon source by the SRB. Although the uptake of dihydrogen (H2) is suggested here, direct uptake of electrons from the steel surface by SRB and methanogens has also been suggested (Dinh et al., 2004; Enning et al., 2012).
Mentions: These features are captured in the extended MIC model shown in Figure 9. We have shown the uptake of reducing equivalents (H+ + eāˆ’) as dihydrogen (H2), realizing that direct uptake of electrons is another mechanism that has been proposed (Dinh et al., 2004; Enning et al., 2012). Accordingly, hydrogenotrophic acetogens, methanogens, or SRB could all contribute directly to corrosion by using metallic iron as an electron donor. The combined action of hydrogenotrophic acetogens and acetotrophic methanogens would be the same as that of hydrogenotrophic methanogens alone. In the coupon-attached biofilms for P0866, P0866S, and P0848S, the hydrogenotrophic Methanobacteriaceae predominated (Table 2: 71.75ā€“89.31%), whereas the PW7 biofilm had a high fraction of Acetobacterium (2.93%) and of the acetotrophic Methanosaeta (17.14%).

Bottom Line: Through a mechanism, that is still poorly understood, electrons or hydrogen (H2) molecules are removed from the metal surface and used as electron donor for sulfate reduction.The resulting ferrous ions precipitate in part with the sulfide produced, forming characteristic black iron sulfide.An extended MIC model capturing these results is presented.

View Article: PubMed Central - PubMed

Affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada.

ABSTRACT
Microbially influenced corrosion (MIC) of iron (Fe(0)) by sulfate-reducing bacteria (SRB) has been studied extensively. Through a mechanism, that is still poorly understood, electrons or hydrogen (H2) molecules are removed from the metal surface and used as electron donor for sulfate reduction. The resulting ferrous ions precipitate in part with the sulfide produced, forming characteristic black iron sulfide. Hydrogenotrophic methanogens can also contribute to MIC. Incubation of pipeline water samples, containing bicarbonate and some sulfate, in serum bottles with steel coupons and a headspace of 10% (vol/vol) CO2 and 90% N2, indicated formation of acetate and methane. Incubation of these samples in serum bottles, containing medium with coupons and bicarbonate but no sulfate, also indicated that formation of acetate preceded the formation of methane. Microbial community analyses of these enrichments indicated the presence of Acetobacterium, as well as of hydrogenotrophic and acetotrophic methanogens. The formation of acetate by homoacetogens, such as Acetobacterium woodii from H2 (or Fe(0)) and CO2, is potentially important, because acetate is a required carbon source for many SRB growing with H2 and sulfate. A consortium of the SRB Desulfovibrio vulgaris Hildenborough and A. woodii was able to grow in defined medium with H2, CO2, and sulfate, because A. woodii provides the acetate, needed by D. vulgaris under these conditions. Likewise, general corrosion rates of metal coupons incubated with D. vulgaris in the presence of acetate or in the presence of A. woodii were higher than in the absence of acetate or A. woodii, respectively. An extended MIC model capturing these results is presented.

No MeSH data available.


Related in: MedlinePlus