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| Registros recuperados : 17 | |
| 12. |  | NUNES, V. da S.; MIRANDA, J. R.; BARBOSA, M. F. de S. Game hunting by rubber tappers of the Tejo River Basin, Acre state, Brazil. GEE - Grupo de Estudos Ecológicos, Universidade de Barcelona-Madri, p. 1-15, 1997. broch., monocr., A4 (Série Documentos, 5)| Biblioteca(s): Embrapa Territorial. |
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| 15. | | VIEIRA, L. M.; GALDINO, S.; PADOVANI, C. R.; NUNES, V. da S. Risco de contaminacao do Pantanal por biocidas empregados na agropecuaria da Bacia do Alto Taquari, MS, Brasil. Separata de Revista Brasileira de Toxicologia, São Paulo, v.12, n.1, ed. esp., p.43, 1999. Simposio de Toxicologia, 1999, Ribeirao Preto. Agricultura e preservacao da qualidade da agua - resumos.| Biblioteca(s): Embrapa Pantanal. |
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| 16. | | VIEIRA, L. M.; NUNES, V. da S.; AMARAL, M. C. R. do; OLIVEIRA, A. C.; CAMPOS, R. C. de. Níveis de mercúrio (HG) em jacarés (Caiman crocodilus yacare) do Pantanal. In: SIMPÓSIO SOBRE RECURSOS NATURAIS E SÓCIO-ECONÔMICOS DO PANTANAL, 4., 2004, Corumbá, MS. Sustentabilidade regional: anais. Corumbá: Embrapa Pantanal: UCDB: UFMS: SEBRAE-MS, 2004. (CD-ROM).| Biblioteca(s): Embrapa Pantanal. |
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| 17. | | RIEDER, A.; DORES, E. F. G. de C.; NUNES, V. da S.; OLIVEIRA, M. D. de; MOZETO, A. A.; MODRO, A. F. H.; SANTOS, J. L. dos; ROCHA, G. S. Classes de potencial de Periculosidade Ambiental (PPA) dos pesticidas receitados em Municípios do Pantanal Norte, Mato Grosso (MT), Brasil, no biênio 1999-2000. In: SIMPÓSIO SOBRE RECURSOS NATURAIS E SÓCIO-ECONÔMICOS DO PANTANAL, 4., 2004, Corumbá, MS. Sustentabilidade regional: anais. Corumbá: Embrapa Pantanal: UCDB: UFMS: SEBRAE-MS, 2004. (CD-ROM).| Biblioteca(s): Embrapa Pantanal. |
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| Registros recuperados : 17 | |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Pantanal. Para informações adicionais entre em contato com cpap.biblioteca@embrapa.br. |
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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