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Registro Completo |
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Biblioteca(s): |
Embrapa Pantanal. |
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Data corrente: |
10/08/1999 |
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Data da última atualização: |
28/03/2017 |
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Autoria: |
DURAN, N. L.; SMITH, G. B.; NUNES, V. da S. |
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Afiliação: |
New Mexico State University (Las Cruces, USA); EMBRAPA Pantanal (Corumba, MS). |
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Título: |
The dehalogenation kinetics of CFC-11. |
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Ano de publicação: |
1998 |
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Fonte/Imprenta: |
In: LATIN AMERICAN BIODEGRADATION & BIODETERIORATION SYMPOSIUM, 3., 1998, Florianopolis. Anais... Florianopolis: UFSC, 1998. p.1-5. |
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Idioma: |
Inglês |
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Conteúdo: |
The kinetics of biodegradation provides an objective basis for evaluation the fate of contaminants and their persistence in the environment. Information about degradation rates is very important from the bioremediation standpoint. The objective of this study was to determine the kinetic parameters for the dehalogenation of CFC-11 to HCFC-21, previously reported by our laboratory. Batch experiments were performed using an enriched mixed culture of sulfate-reducing bacteria that originated from groundwater samples obtained from aquifer contamined with CFC-11 and other halogenated aliphatic compunds. When substrate depletion curves with initial concentrations of 1.6uM were analyzed, good linearity was obtained when fitted to the Henri-Michaelis-Menten equation. The kinetic parameters associated with the microbial dehalogenation of CFC-11 to HCFC-21 were calculated by linear regression to be Km=1.29uM and Vm=0.598 uM h-1. The first-order rate constant (k1) was determined to be 4.6 x 10-2h-1. An acute toxicity effect was observed at 8.34uM CFC-11, while concentrations below 0.04uM were biologically unavailable. Since the availability of electron acceptors has been known to affect the flow of electrons required for reductive dehalogenation reactions, alternative electron acceptors were tested. It was found that only sulfate supported the dehalogenation reaction while sulfite and thiosulfate did not. The addition of sulfate-reducing inhibitors, selenate or molybdate, to an actively degrading sulfate-grown culture inhibited the dehalogenation reaction. A model is proposed for the mechanism of electron flow patterns in the reduction of CFC-11. MenosThe kinetics of biodegradation provides an objective basis for evaluation the fate of contaminants and their persistence in the environment. Information about degradation rates is very important from the bioremediation standpoint. The objective of this study was to determine the kinetic parameters for the dehalogenation of CFC-11 to HCFC-21, previously reported by our laboratory. Batch experiments were performed using an enriched mixed culture of sulfate-reducing bacteria that originated from groundwater samples obtained from aquifer contamined with CFC-11 and other halogenated aliphatic compunds. When substrate depletion curves with initial concentrations of 1.6uM were analyzed, good linearity was obtained when fitted to the Henri-Michaelis-Menten equation. The kinetic parameters associated with the microbial dehalogenation of CFC-11 to HCFC-21 were calculated by linear regression to be Km=1.29uM and Vm=0.598 uM h-1. The first-order rate constant (k1) was determined to be 4.6 x 10-2h-1. An acute toxicity effect was observed at 8.34uM CFC-11, while concentrations below 0.04uM were biologically unavailable. Since the availability of electron acceptors has been known to affect the flow of electrons required for reductive dehalogenation reactions, alternative electron acceptors were tested. It was found that only sulfate supported the dehalogenation reaction while sulfite and thiosulfate did not. The addition of sulfate-reducing inhibitors, selenate or molybdate, to an actively... Mostrar Tudo |
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Palavras-Chave: |
Xenobiotico. |
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Thesagro: |
Biodegradação; Substancia Tóxica. |
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Thesaurus Nal: |
biodegradation; xenobiotics. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 02269naa a2200205 a 4500
001 1798446
005 2017-03-28
008 1998 bl --- 0-- u #d
100 1 $aDURAN, N. L.
245 $aThe dehalogenation kinetics of CFC-11.
260 $c1998
520 $aThe kinetics of biodegradation provides an objective basis for evaluation the fate of contaminants and their persistence in the environment. Information about degradation rates is very important from the bioremediation standpoint. The objective of this study was to determine the kinetic parameters for the dehalogenation of CFC-11 to HCFC-21, previously reported by our laboratory. Batch experiments were performed using an enriched mixed culture of sulfate-reducing bacteria that originated from groundwater samples obtained from aquifer contamined with CFC-11 and other halogenated aliphatic compunds. When substrate depletion curves with initial concentrations of 1.6uM were analyzed, good linearity was obtained when fitted to the Henri-Michaelis-Menten equation. The kinetic parameters associated with the microbial dehalogenation of CFC-11 to HCFC-21 were calculated by linear regression to be Km=1.29uM and Vm=0.598 uM h-1. The first-order rate constant (k1) was determined to be 4.6 x 10-2h-1. An acute toxicity effect was observed at 8.34uM CFC-11, while concentrations below 0.04uM were biologically unavailable. Since the availability of electron acceptors has been known to affect the flow of electrons required for reductive dehalogenation reactions, alternative electron acceptors were tested. It was found that only sulfate supported the dehalogenation reaction while sulfite and thiosulfate did not. The addition of sulfate-reducing inhibitors, selenate or molybdate, to an actively degrading sulfate-grown culture inhibited the dehalogenation reaction. A model is proposed for the mechanism of electron flow patterns in the reduction of CFC-11.
650 $abiodegradation
650 $axenobiotics
650 $aBiodegradação
650 $aSubstancia Tóxica
653 $aXenobiotico
700 1 $aSMITH, G. B.
700 1 $aNUNES, V. da S.
773 $tIn: LATIN AMERICAN BIODEGRADATION & BIODETERIORATION SYMPOSIUM, 3., 1998, Florianopolis. Anais... Florianopolis: UFSC, 1998. p.1-5.
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Registro original: |
Embrapa Pantanal (CPAP) |
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| 1. |  | OLIVEIRA, L. V.; NABINGER, C.; GENRO, T. C. M.; NALERIO, E. S.; GIONGO, C.; KINDLEIN, L.; GARAGORRY, F. C.; LANNA, D. P. D.; COSTA, J. L. B.; SARAIVA, A. C. Composição química da carne de bovinos da raça Hereford submetidos a sistemas pastoris com ou sem aporte de insumos no Sul do Brasil. In: REUNIÓN DEL GRUPO TÉCNICO EN FORRAJERAS DEL CONO SUR, 24., 2017, Tacuarembó. Bioma Campos: retomando un camino de oportunidades para una producción ganadera sustentable: memorias. [Tacuarembó]: INIA: UDELAR, 2017. p. 183-185.| Tipo: Artigo em Anais de Congresso |
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