title: Anaerobic hydrocarbon and fatty acid metabolism by syntrophic bacteria and their impact on carbon steel corrosion.
abstract: The microbial metabolism of hydrocarbons is increasingly associated with the corrosion of carbon steel in sulfate-rich marine waters. However, how such transformations influence metal biocorrosion in the absence of an electron acceptor is not fully recognized. We grew a marine alkane-utilizing, sulfate-reducing bacterium, Desulfoglaeba alkanexedens, with either sulfate or Methanospirillum hungatei as electron acceptors, and tested the ability of the cultures to catalyze metal corrosion. Axenically, D. alkanexedens had a higher instantaneous corrosion rate and produced more pits in carbon steel coupons than when the same organism was grown in syntrophic co-culture with the methanogen. Since anaerobic hydrocarbon biodegradation pathways converge on fatty acid intermediates, the corrosive ability of a known fatty acid-oxidizing syntrophic bacterium, Syntrophus aciditrophicus was compared when grown in pure culture or in co-culture with a H2-utilizing sulfate-reducing bacterium (Desulfovibrio sp., strain G11) or a methanogen (M. hungatei). The instantaneous corrosion rates in the cultures were not substantially different, but the syntrophic, sulfate-reducing co-culture produced more pits in coupons than other combinations of microorganisms. Lactate-grown cultures of strain G11 had higher instantaneous corrosion rates and coupon pitting compared to the same organism cultured with hydrogen as an electron donor. Thus, if sulfate is available as an electron acceptor, the same microbial assemblages produce sulfide and low molecular weight organic acids that exacerbated biocorrosion. Despite these trends, a surprisingly high degree of variation was encountered with the corrosion assessments. Differences in biomass, initial substrate concentration, rates of microbial activity or the degree of end product formation did not account for the variations. We are forced to ascribe such differences to the metallurgical properties of the coupons.
authors.affiliation: Department of Microbiology and Plant Biology, Institute for Energy and the Environment, and the OU Biocorrosion Center, University of Oklahoma Norman, OK, USA.
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Lyles
authors.affiliation: Department of Microbiology and Plant Biology, Institute for Energy and the Environment, and the OU Biocorrosion Center, University of Oklahoma Norman, OK, USA.
authors.forename: Huynh M
authors.initials: HM
authors.lastname: Le
authors.affiliation: Howard Live Oak, LLC Norman, OK, USA.
authors.forename: William Howard
authors.initials: WH
authors.lastname: Beasley
authors.affiliation: Department of Microbiology and Plant Biology, Institute for Energy and the Environment, and the OU Biocorrosion Center, University of Oklahoma Norman, OK, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: McInerney
authors.affiliation: Department of Microbiology and Plant Biology, Institute for Energy and the Environment, and the OU Biocorrosion Center, University of Oklahoma Norman, OK, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Suflita
keywords: biocorrosion; fatty acid oxidation; hydrocarbon degradation; microbiologically influenced corrosion (MIC); syntrophy
references.citation: Arch Microbiol. 1999 Jan;171(2):107-14
references.pmid: 9914307
references.citation: Int J Syst Evol Microbiol. 2006 Dec;56(Pt 12):2737-2742
references.pmid: 17158970
references.citation: Proc Natl Acad Sci U S A. 2007 May 1;104(18):7600-5
references.pmid: 17442750
references.citation: Nature. 2008 Jan 10;451(7175):176-80
references.pmid: 18075503
references.citation: Appl Environ Microbiol. 2008 May;74(10):3022-9
references.pmid: 18378655
references.citation: Annu Rev Pharmacol Toxicol. 1992;32:109-34
references.pmid: 1605565
references.citation: Appl Environ Microbiol. 1999 Aug;65(8):3502-11
references.pmid: 10427041
references.citation: PLoS One. 2009 Jun 04;4(6):e5797
references.pmid: 19495416
references.citation: Nature. 1971 Oct 15;233(5320):491-2
references.pmid: 16063454
references.citation: Environ Sci Technol. 2013 Jun 4;47(11):6052-62
references.pmid: 23614475
references.citation: Appl Environ Microbiol. 2014 Feb;80(4):1226-36
references.pmid: 24317078
references.citation: Appl Environ Microbiol. 1996 Jan;62(1):26-32
references.pmid: 16535215
references.citation: Nature. 2004 Feb 26;427(6977):829-32
references.pmid: 14985759
references.citation: Antonie Van Leeuwenhoek. 2000 Feb;77(2):103-16
references.pmid: 10768470
references.citation: FEMS Microbiol Ecol. 2011 May;76(2):289-300
references.pmid: 21223338
references.citation: Biotechnol Prog. 2001 Sep-Oct;17(5):852-9
references.pmid: 11587574
references.citation: Annu Rev Microbiol. 1985;39:195-217
references.pmid: 3904600
references.citation: Science. 1988 Mar 4;239(4844):1129-31
references.pmid: 17791972
references.citation: Appl Environ Microbiol. 1986 Jun;51(6):1205-11
references.pmid: 16347078
references.citation: Appl Environ Microbiol. 2007 Apr;73(8):2644-52
references.pmid: 17308184
references.citation: ISME J. 2008 Apr;2(4):442-52
references.pmid: 18079730
references.citation: Appl Environ Microbiol. 2010 Mar;76(6):1783-8
references.pmid: 20118376
references.citation: Front Microbiol. 2013 May 14;4:89
references.pmid: 23717304
references.citation: Appl Environ Microbiol. 1995 Feb;61(2):526-30
references.pmid: 7574591
references.citation: Appl Environ Microbiol. 2007 Feb;73(3):930-8
references.pmid: 17158621
references.citation: Environ Microbiol. 2012 Jul;14(7):1772-87
references.pmid: 22616633
references.citation: Nat Commun. 2013;4:1998
references.pmid: 23759740