title: Examining thiosulfate-driven autotrophic denitrification through respirometry.
abstract: Anoxic respirometry was applied to characterize a sulfide-oxidizing nitrate-reducing (SO-NR) culture obtained from an anoxic biogas desulfurizing biotrickling filter treating high loads of H2S. Immobilized biomass extracted from the biotrickling filter was grown in a suspended culture with thiosulfate as electron donor to obtain the biomass growth yield and the S2O3(2)(-)/NO3(-) consumed ratio. Afterward, respirometry was applied to describe thiosulfate oxidation under anoxic conditions. A pure culture of Thiobacillus denitrificans was also used as a control culture in order to validate the procedure proposed in this work to characterize the SO-NR biomass. Respirometric profiles obtained with this microbial culture showed that nitrite was formed as intermediate during nitrate reduction and revealed that no competitive inhibition appeared when both electron acceptors were present in the medium. Although final bioreaction products depended on the initial S2O3(2)(-)/NO3(-) ratio, such ratio did not affect thiosulfate oxidation or denitrification rates. Moreover, respirometric profiles showed that the specific nitrite uptake rate depended on the biomass characteristics being that of a SO-NR mixed culture (39.8mgNg(-1) VSSh(-1)) higher than that obtained from a pure culture of T. denitrificans (19.7mgNg(-1) VSSh(-1)). For the first time, the stoichiometry of the two-step denitrification mechanism with thiosulfate oxidation and biomass growth associated was solved for both reactions.
authors: Department of Chemical Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Mabel
authors: M
authors: Mora
authors: Department of Chemical Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors: Albert
authors: A
authors: Guisasola
authors: Department of Mining Engineering and Natural Resources, Universitat Politècnica de Catalunya, Bases de Manresa 61-73, 08240 Manresa, Spain.
authors: Xavier
authors: X
authors: Gamisans
authors: Department of Chemical Engineering, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. Electronic address: David.Gabriel@uab.cat.
authors: David
authors: D
authors: Gabriel
mesh_terms: D000693:Anaerobiosis; D052818:Autotrophic Processes / Q000502:physiology*; D056804:Biofuels; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D058440:Denitrification / Q000502:physiology*; D005374:Filtration / Q000295:instrumentation*; D008954:Models, Biological; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009589:Nitrogen Oxides / Q000378:metabolism; D010084:Oxidation-Reduction; D013440:Sulfides / Q000378:metabolism; D013855:Thiobacillus / Q000378:metabolism*; D013885:Thiosulfates / Q000378:metabolism*
chemical_list: D056804:Biofuels; D009566:Nitrates; D009573:Nitrites; D009589:Nitrogen Oxides; D013440:Sulfides; D013885:Thiosulfates
keywords: Biotrickling filters; Desulfurization; Respirometry; Stoichiometry; Sulfur-oxidizing nitrogen-reducing cultures