title: Use of Acetate, Propionate, and Butyrate for Reduction of Nitrate and Sulfate and Methanogenesis in Microcosms and Bioreactors Simulating an Oil Reservoir.
abstract: Acetate, propionate, and butyrate (volatile fatty acids [VFA]) occur in oil field waters and are frequently used for microbial growth of oil field consortia. We determined the kinetics of use of these VFA components (3 mM each) by an anaerobic oil field consortium in microcosms containing 2 mM sulfate and 0, 4, 6, 8, or 13 mM nitrate. Nitrate was reduced first, with a preference for acetate and propionate. Sulfate reduction then proceeded with propionate (but not butyrate) as the electron donor, whereas the fermentation of butyrate (but not propionate) was associated with methanogenesis. Microbial community analyses indicated thatParacoccusandThauera(Paracoccus-Thauera),Desulfobulbus, andSyntrophomonas-Methanobacteriumwere the dominant taxa whose members catalyzed these three processes. Most-probable-number assays showed the presence of up to 107/ml of propionate-oxidizing sulfate-reducing bacteria (SRB) in waters from the Medicine Hat Glauconitic C field. Bioreactors with the same concentrations of sulfate and VFA responded similarly to increasing concentrations of injected nitrate as observed in the microcosms: sulfide formation was prevented by adding approximately 80% of the nitrate dose needed to completely oxidize VFA to CO2in both. Thus, this work has demonstrated that simple time-dependent observations of the use of acetate, propionate, and butyrate for nitrate reduction, sulfate reduction, and methanogenesis in microcosms are a good proxy for these processes in bioreactors, monitoring of which is more complex.IMPORTANCEOil field volatile fatty acids acetate, propionate, and butyrate were specifically used for nitrate reduction, sulfate reduction, and methanogenic fermentation. Time-dependent analyses of microcosms served as a good proxy for these processes in a bioreactor, mimicking a sulfide-producing (souring) oil reservoir: 80% of the nitrate dose required to oxidize volatile fatty acids to CO2was needed to prevent souring in both. Our data also suggest that propionate is a good substrate to enumerate oil field SRB.
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada cchen@hit.edu.cn.|State Key laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, HeiLongjiang Province, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Chen
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Yin
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Dongshan
authors.initials: D
authors.lastname: An
authors.affiliation: Petroleum Microbiology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Voordouw
mesh_terms: D000085:Acetates / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors; D020148:Butyric Acid / Q000378:metabolism; D003198:Computer Simulation; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D008697:Methane / Q000096:biosynthesis* / Q000378:metabolism; D059013:Microbial Consortia; D009566:Nitrates / Q000378:metabolism* / Q000494:pharmacology; D061329:Oil and Gas Fields; D010084:Oxidation-Reduction; D010230:Paracoccus / Q000302:isolation & purification / Q000378:metabolism; D011422:Propionates / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism*
chemical_list: D000085:Acetates; D005232:Fatty Acids, Volatile; D009566:Nitrates; D011422:Propionates; D013431:Sulfates; D020148:Butyric Acid; D008697:Methane
keywords: butyrate oxidation; methanogenesis; nitrate dose; nitrate injection; propionate oxidation; souring control; syntrophic degradation