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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

Field samples were incubated in CSB-K medium with carbon steel coupons. Acetate (A) and methane (B) concentrations were monitored during incubation. Corrosion rates (C) were determined from metal weight loss. Data represent results from separate incubations with two coupons each.
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Figure 3: Field samples were incubated in CSB-K medium with carbon steel coupons. Acetate (A) and methane (B) concentrations were monitored during incubation. Corrosion rates (C) were determined from metal weight loss. Data represent results from separate incubations with two coupons each.

Mentions: In a variation of this experiment serum bottles with 70 mL CSB-K medium, containing carbon steel coupons, 30 mM of bicarbonate and a headspace of N2-CO2 were inoculated with 3.5 ml of field sample. Acetate and methane were monitored as a function of time, and weight loss corrosion was determined at the end of the experiment. Production of up to 0.6 mM acetate was seen for all samples. This appeared to precede production of methane and go through a maximum (Figure 3A). Production of 1.9 to 3.0 mM headspace methane was observed with all samples, except P0866 (Figure 3B). The biofilms present on the coupons were isolated prior to processing of the coupons for measuring weight loss corrosion. The corrosion rates observed for incubations with samples PW7, P0866S, and P0848S (average 0.0068 ± 0.0012 mm/year, n = 6) were higher (p < 0.00076) than those with P0866 and the medium control (average 0.0035 ± 0.00031 mm/year, n = 4), as shown in Figure 3C. Hence, although both acetate and methane were formed as part of the corrosion process, the formation of headspace methane appeared to be correlated with the corrosion rate, i.e., P0866S, the sample with the highest corrosion rate (0.0083 mm/yr) also had the highest headspace methane concentration (3.0 mM).


The role of acetogens in microbially influenced corrosion of steel.

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

Field samples were incubated in CSB-K medium with carbon steel coupons. Acetate (A) and methane (B) concentrations were monitored during incubation. Corrosion rates (C) were determined from metal weight loss. Data represent results from separate incubations with two coupons each.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Field samples were incubated in CSB-K medium with carbon steel coupons. Acetate (A) and methane (B) concentrations were monitored during incubation. Corrosion rates (C) were determined from metal weight loss. Data represent results from separate incubations with two coupons each.
Mentions: In a variation of this experiment serum bottles with 70 mL CSB-K medium, containing carbon steel coupons, 30 mM of bicarbonate and a headspace of N2-CO2 were inoculated with 3.5 ml of field sample. Acetate and methane were monitored as a function of time, and weight loss corrosion was determined at the end of the experiment. Production of up to 0.6 mM acetate was seen for all samples. This appeared to precede production of methane and go through a maximum (Figure 3A). Production of 1.9 to 3.0 mM headspace methane was observed with all samples, except P0866 (Figure 3B). The biofilms present on the coupons were isolated prior to processing of the coupons for measuring weight loss corrosion. The corrosion rates observed for incubations with samples PW7, P0866S, and P0848S (average 0.0068 ± 0.0012 mm/year, n = 6) were higher (p < 0.00076) than those with P0866 and the medium control (average 0.0035 ± 0.00031 mm/year, n = 4), as shown in Figure 3C. Hence, although both acetate and methane were formed as part of the corrosion process, the formation of headspace methane appeared to be correlated with the corrosion rate, i.e., P0866S, the sample with the highest corrosion rate (0.0083 mm/yr) also had the highest headspace methane concentration (3.0 mM).

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