AplicaciĆ³n de bacterias resistentes a metal(oid)es para la remociĆ³n de estos contaminantes desde matrices acuosas
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Fecha
2018
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es
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Universidad AndrƩs Bello
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Licencia CC
Licencia CC
Resumen
El aumento en la contaminaciĆ³n del aire, suelos, aguas subterrĆ”neas y de regadĆo se ha convertido en un problema dado el impacto negativo que provoca en el ecosistema y que en el corto plazo podrĆa afectar directamente la poblaciĆ³n humana. La mayorĆa de los contaminantes presentes en los ecosistemas acuĆ”ticos son compuestos orgĆ”nicos y/o metales pesados, una consecuencia de la actividad antropogĆ©nica no regulada. En esta lĆnea, se ha desarrollado una amplia gama de alternativas tecnolĆ³gicas entre las que destaca la biorremediaciĆ³n por sus caracterĆsticas traducibles en bajos costos de operaciĆ³n y mantenciĆ³n respecto a mĆ©todos fĆsicos y/o quĆmicos.
Acorde con el creciente uso de microorganismos para remediar aguas contaminadas, el objetivo de esta Tesis fue analizar la remociĆ³n de metal(oides), especĆficamente telurito, arsenito, cadmio y cobre, por bacterias ambientales resistentes a estos compuestos en condiciones aerĆ³bicas y anĆ³xicas. La remociĆ³n se llevĆ³ a cabo utilizando medio mĆnimo SV.3, formulado especĆficamente para mantener la solubilidad de los metales a pH neutro. Los cultivos se llevaron a cabo en presencia o ausencia de oxĆgeno en ensayos de 24 h donde se cuantificĆ³ la concentraciĆ³n del tĆ³xico al inicio y final del proceso.
En ambas condiciones de crecimiento, las bacterias removieron telurito > arsenito > cobre. No fue posible cuantificar la remociĆ³n de cadmio. Dado que promueve un mayor crecimiento bacteriano, la condiciĆ³n anaerĆ³bica resultĆ³ mĆ”s eficiente en la remociĆ³n de los tĆ³xicos ensayados. Finalmente, este proceso de biorremediaciĆ³n permite recuperar el escaso metaloide teluro, de alto valor tecnolĆ³gico. AdemĆ”s, se podrĆa descontaminar arsenito, altamente tĆ³xico y abundante en una variedad de ambientes que se encuentran en contacto con las poblaciones humanas.
The increasing contamination of air, soil and water has become a problem because they impact negatively different ecosystems that in the short term could affect directly human health. As consequence of a non-regulated anthropogenic activity, most contaminants present in aquatic ecosystems are organic compounds and/or heavy metals. In this line, a number of technological alternatives have emerged, including bioremediation, which exhibits rather low operation costs as compared to other chemical and physical methods. In agreement with the increasing use of microorganisms to treat polluted water systems, the goal of this Thesis work was to assess removal of metal(loid)s, specifically tellurite, arsenite, cadmium and copper by toxicant-resistant environmental bacteria under aerobic and anaerobic conditions. Removal was accomplished by using SV.3 minimal growth medium, specially designed to allow metal(loid) solubility at neutral pH values. Cultures were for 24 h in the presence or absence of oxygen and the toxicantĀ“s concentration was assessed at the beginning and ending of the process. In both conditions bacterial removal was tellurite > arsenite > copper. Cadmium removal could not be determined. Given it promotes a better bacterial growth, the anaerobic condition showed to be more efficient in toxicant removal. Finally, while allowing the recovery of the scarce metalloid tellurium -which exhibits great technological value- this process, is also efficient to remove arsenic, a highly toxicant element that profuses in many places that are in contact with humans.
The increasing contamination of air, soil and water has become a problem because they impact negatively different ecosystems that in the short term could affect directly human health. As consequence of a non-regulated anthropogenic activity, most contaminants present in aquatic ecosystems are organic compounds and/or heavy metals. In this line, a number of technological alternatives have emerged, including bioremediation, which exhibits rather low operation costs as compared to other chemical and physical methods. In agreement with the increasing use of microorganisms to treat polluted water systems, the goal of this Thesis work was to assess removal of metal(loid)s, specifically tellurite, arsenite, cadmium and copper by toxicant-resistant environmental bacteria under aerobic and anaerobic conditions. Removal was accomplished by using SV.3 minimal growth medium, specially designed to allow metal(loid) solubility at neutral pH values. Cultures were for 24 h in the presence or absence of oxygen and the toxicantĀ“s concentration was assessed at the beginning and ending of the process. In both conditions bacterial removal was tellurite > arsenite > copper. Cadmium removal could not be determined. Given it promotes a better bacterial growth, the anaerobic condition showed to be more efficient in toxicant removal. Finally, while allowing the recovery of the scarce metalloid tellurium -which exhibits great technological value- this process, is also efficient to remove arsenic, a highly toxicant element that profuses in many places that are in contact with humans.
Notas
Tesis (MagĆster en BiotecnologĆa)
Palabras clave
BiorremediaciĆ³n, Metales Pesados, Aspectos Ambientales