Limits...
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

Corrosion rates of carbon steel coupons incubated in closed serum bottles with monocultures and a coculture of A. woodii (Aw) and D. vulgaris (Dv) an atmosphere of either (A) 90% N2, 10% (B) 16% H2, 84% CO2,or (C) 80% H2, 20% CO2. Control bottles had no inoculum. Data represent average results from two separate incubations with two coupons each.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4043135&req=5

Figure 8: Corrosion rates of carbon steel coupons incubated in closed serum bottles with monocultures and a coculture of A. woodii (Aw) and D. vulgaris (Dv) an atmosphere of either (A) 90% N2, 10% (B) 16% H2, 84% CO2,or (C) 80% H2, 20% CO2. Control bottles had no inoculum. Data represent average results from two separate incubations with two coupons each.

Mentions: When carbon steel coupons were added to serum bottles, containing WP medium with sulfate and bicarbonate and a headspace of N2-CO2 and inoculated with D. vulgaris, D. vulgaris and 3 mM acetate, A. woodii, D. vulgaris, and A. woodii, or no inoculum, similar corrosion rates were observed of 0.0039 to 0.0055 mm/yr in all incubations (Figure 8C). This indicates that Fe0 alone is not a good electron donor for sulfate or carbon dioxide reduction by these two type cultures. In order to determine whether Fe0 can be used as an electron donor co-metabolically with H2, the experiment was repeated with a headspace of 80% (vol/vol) H2 and 20% CO2 (excess H2 for reduction of 10 mM sulfate) or 16% H2 and 84% CO2 (insufficient H2 for reduction of 10 mM sulfate). The highest corrosion rates were observed with limiting H2 for incubations with D. vulgaris and 3 mM acetate (0.0113 mm/yr) or with the coculture of D. vulgaris and A. woodii (0.0104 mm/yr), as shown in Figure 8B. These were higher (p < 0.000068) than the corrosion rates observed for incubations with D. vulgaris alone without added acetate, with A. woodii alone or with the uninoculated control (average 0.0074 ± 0.0015 mm/yr, n = 12). In the presence of excess H2 lower corrosion rates, between 0.0054 and 0.0059 mm/yr, were observed for all incubations except for the co-culture, which was somewhat higher (0.0076 mm/yr), as shown in Figure 8A. Overall, these results indicate that the co-culture of D. vulgaris and A. woodii can co-metabolically corrode carbon steel at a rate comparable to that when acetate is provided directly to the D. vulgaris culture.


The role of acetogens in microbially influenced corrosion of steel.

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

Corrosion rates of carbon steel coupons incubated in closed serum bottles with monocultures and a coculture of A. woodii (Aw) and D. vulgaris (Dv) an atmosphere of either (A) 90% N2, 10% (B) 16% H2, 84% CO2,or (C) 80% H2, 20% CO2. Control bottles had no inoculum. Data represent average results from two 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 8: Corrosion rates of carbon steel coupons incubated in closed serum bottles with monocultures and a coculture of A. woodii (Aw) and D. vulgaris (Dv) an atmosphere of either (A) 90% N2, 10% (B) 16% H2, 84% CO2,or (C) 80% H2, 20% CO2. Control bottles had no inoculum. Data represent average results from two separate incubations with two coupons each.
Mentions: When carbon steel coupons were added to serum bottles, containing WP medium with sulfate and bicarbonate and a headspace of N2-CO2 and inoculated with D. vulgaris, D. vulgaris and 3 mM acetate, A. woodii, D. vulgaris, and A. woodii, or no inoculum, similar corrosion rates were observed of 0.0039 to 0.0055 mm/yr in all incubations (Figure 8C). This indicates that Fe0 alone is not a good electron donor for sulfate or carbon dioxide reduction by these two type cultures. In order to determine whether Fe0 can be used as an electron donor co-metabolically with H2, the experiment was repeated with a headspace of 80% (vol/vol) H2 and 20% CO2 (excess H2 for reduction of 10 mM sulfate) or 16% H2 and 84% CO2 (insufficient H2 for reduction of 10 mM sulfate). The highest corrosion rates were observed with limiting H2 for incubations with D. vulgaris and 3 mM acetate (0.0113 mm/yr) or with the coculture of D. vulgaris and A. woodii (0.0104 mm/yr), as shown in Figure 8B. These were higher (p < 0.000068) than the corrosion rates observed for incubations with D. vulgaris alone without added acetate, with A. woodii alone or with the uninoculated control (average 0.0074 ± 0.0015 mm/yr, n = 12). In the presence of excess H2 lower corrosion rates, between 0.0054 and 0.0059 mm/yr, were observed for all incubations except for the co-culture, which was somewhat higher (0.0076 mm/yr), as shown in Figure 8A. Overall, these results indicate that the co-culture of D. vulgaris and A. woodii can co-metabolically corrode carbon steel at a rate comparable to that when acetate is provided directly to the D. vulgaris culture.

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