Estudio de los mecanismos de remoción de pentaclorofenol por Rhizopus oryzae ENHE
The PCP contamination into environment started at the beginning of 20th century and unfortunately persists nowadays because of the recalcitrant nature of this pollutant. Fungi had been a great alternative to degrade pollutants since they can remove them by physicochemical procedures, in some cases u...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:nz805z87x |
| Acceso en línea: | https://doi.org/10.24275/uami.nz805z87x |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Pentaclorofenol -- Aspectos ambientales info:eu-repo/classification/LEM/Contaminación de suelos info:eu-repo/classification/LEM/Food contamination info:eu-repo/classification/LEM/Biotechnology info:eu-repo/classification/LEM/Water Purification Waste disposal info:eu-repo/classification/LEM/Biotecnología info:eu-repo/classification/LEM/Rhizopus oryzae ENHE info:eu-repo/classification/LEM/Contaminación de alimentos info:eu-repo/classification/LEM/Agua -- Purificación -- Eliminación de compuestos químicos info:eu-repo/classification/LEM/Pesticides Environmental aspects info:eu-repo/classification/LEM/Soil pollution info:eu-repo/classification/cti/6 |
| Sumario: | The PCP contamination into environment started at the beginning of 20th century and unfortunately persists nowadays because of the recalcitrant nature of this pollutant. Fungi had been a great alternative to degrade pollutants since they can remove them by physicochemical procedures, in some cases until mineralization. Rhizopus oryzae ENHE (CDBB-H-1877), a zygomycete isolated from PCP-contaminated soil, is a filamentous fungus that it is able to remove PCP. In this work it was showed that R. oryzae ENHE can remove PCP by means three mechanisms; two of which are related to the partial degradation of PCP and are metabolically dependents. Biosorption was the main mechanism of PCP removal. The sorption of PCP on dried powdered biomass was reversible, dependent of temperature and it was increased at pH 5.0, where the maximum sorption capacity of PCP was 16.99 mg PCP g-1 biomass. On the other hand, the maximum sorption capacity of PCP was 37.09 mg PCP g-1 biomass at pH 3.3 using a wet weight biomass. R. oryzae ENHE uses both methylation and dechlorination reactions as metabolic strategies to degrade PCP. However, the presence of this xenobiotic in the R. oryzae ENHE cultures affected its respiratory capacity, its growth, its biomass yield coefficient, its specific growth rate and its specific substrate uptake rate. It was demonstrated that PCP was mainly degraded inside of the fungus cells because of little amount of intermediates quantified in the broth. When the fungus was cultivated into a mineral medium with glucose and (NH4)2SO2, as carbon and nitrogen sources, and 2 mg of PCP it was yielded 0.116 µg of pentachloroanisole, 10.46 µg chlorinated compounds and six unidentified chlorinated compounds, two of which may be 2,3,4,6-tetrachlorophenol and lactate of PCP. However, when glutamic acid and NaNO3 were used as carbon and nitrogen sources, it was yielded 6.81 µg of pentachloroanisole, 2.89 µg chlorinated compounds and four unidentified chlorinated compounds. R. oryzae ENHE was also cultivated in a stirring tank reactor. Preliminary results indicated that possibly some intermediates of PCP metabolism may form chlorinated dimeric and/or polymeric structures. It is necessary more investigation about that, however, it is clear that some culture variables, such as: aeration and agitation may promote the formation of degradation products of PCP difficult to identity in culture flasks. |
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