title: Inhibitory effects of nitrate reduction on methanogenesis in the presence of different electron donors.
abstract: The preferential utilization of different electron donors and their effects on the nitrate reduction and methanogenesis in a mixed, mesophilic (35 degrees C) methanogenic culture were investigated. Batch methanogenic cultures were fed with dextrin/peptone (D/P), propionate, acetate, and H(2)/CO(2) at an initial COD of 500 mg/L and an initial nitrate concentration of 50 mg N/L. Immediate cessation of methane production was observed in all nitrate-amended cultures. Methane production completely recovered in the D/P- and acetate-fed cultures, and partially recovered or did not recover in the propionate- and H(2)/CO(2)-fed, nitrate-amended cultures, respectively. Accumulation of denitrification intermediates was observed in both the propionate- and H(2)/CO(2)-fed cultures, which resulted in inhibition of fermentation and/or methanogenesis. The fastest and the slowest nitrate reduction were observed in the acetate- and propionate-fed cultures, respectively.
authors.affiliation: School of Civil and Environmental Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0512, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Tugtas
authors.forename: S G
authors.initials: SG
authors.lastname: Pavlostathis
mesh_terms: D000085:Acetates / Q000737:chemistry; D019149:Bioreactors; D002245:Carbon Dioxide / Q000737:chemistry; D003912:Dextrins / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D008697:Methane / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry*; D010084:Oxidation-Reduction; D010461:Peptones / Q000737:chemistry; D011422:Propionates / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D000085:Acetates; D003912:Dextrins; D009566:Nitrates; D010461:Peptones; D011422:Propionates; D002245:Carbon Dioxide; D006859:Hydrogen; D008697:Methane