title: Anaerobic biodegradation of n-hexadecane by a nitrate-reducing consortium.
abstract: Nitrate-reducing enrichments, amended with n-hexadecane, were established with petroleum-contaminated sediment from Onondaga Lake. Cultures were serially diluted to yield a sediment-free consortium. Clone libraries and denaturing gradient gel electrophoresis analysis of 16S rRNA gene community PCR products indicated the presence of uncultured alpha- and betaproteobacteria similar to those detected in contaminated, denitrifying environments. Cultures were incubated with H(34)-hexadecane, fully deuterated hexadecane (d(34)-hexadecane), or H(34)-hexadecane and NaH(13)CO(3). Gas chromatography-mass spectrometry analysis of silylated metabolites resulted in the identification of [H(29)]pentadecanoic acid, [H(25)]tridecanoic acid, [1-(13)C]pentadecanoic acid, [3-(13)C]heptadecanoic acid, [3-(13)C]10-methylheptadecanoic acid, and d(27)-pentadecanoic, d(25)-, and d(2)(4)-tridecanoic acids. The identification of these metabolites suggests a carbon addition at the C-3 position of hexadecane, with subsequent beta-oxidation and transformation reactions (chain elongation and C-10 methylation) that predominantly produce fatty acids with odd numbers of carbons. Mineralization of [1-(14)C]hexadecane was demonstrated based on the recovery of (14)CO(2) in active cultures.
authors.affiliation: Biotechnology Center for Agriculture and the Environment, Rutgers University, School of Environmental and Biological Sciences, New Brunswick, New Jersey 08901-8521, USA.
authors.forename: Amy V
authors.initials: AV
authors.lastname: Callaghan
authors.forename: Meghan
authors.initials: M
authors.lastname: Tierney
authors.forename: Craig D
authors.initials: CD
authors.lastname: Phelps
authors.forename: L Y
authors.initials: LY
authors.lastname: Young
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D020561:Alphaproteobacteria / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D000693:Anaerobiosis; D020562:Betaproteobacteria / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002264:Carboxylic Acids / Q000032:analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D019015:Geologic Sediments / Q000382:microbiology; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000473:Alkanes; D002264:Carboxylic Acids; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C007932:n-hexadecane