Removal of methyl parathion and coumaphos pesticides by a bacterial consortium immobilized in Luffa cylindrica
The constant application of pesticides has led to environmental and health problems in many regions of the world, as well as the storage of large amounts of pesticide waste and obsolete pesticides. For this reason, it is necessary to develop strategies for the disposal of pesticides that are ecofriendly and economically viable. Different treatment options exist, but in recent years, the application of biological systems has gained the greatest acceptance, because it promises the degradation and detoxification of pesticides without harming the environment or human health. In this study, we used a bacterial consortium that was isolated from agricultural soils to degrade a mixture of the organophosphate pesticides methyl parathion (MP) and coumaphos (COU). The efficiency of removal was evaluated using mineral salt medium supplemented with glucose, and the bacterial consortium was cultivated as free cells and immobilized on Luffa cylindrica fibers. To improve the structure of the fibrous network and to achieve greater retention of microorganisms, removal was also tested prior to fibers treatment with sodium hydroxide (NaOH). The results indicate that the microorganisms used had better growth as free cells. A removal of 54.88 % and 62 % for MP and COU, respectively was observed using the free cells; but when the cells were immobilized on loofa sponge fibers, the removal was increased to 98 and 100 % of those pesticides. This pesticide removal was the result of a combined effect among the activity of the microorganisms, the adhesion to the bacterial cells and the adsorption on the support material. We observed a strong and fast adsorption on the loofa sponge fiber, since removal obtained only with loofa fiber, did not present significant difference with immobilized microorganisms. Further studies are needed to understand the processes that occur with adsorbed pesticides and whether there was subsequent desorption and degradation.
| Main Authors: | , , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Universidad Nacional Autónoma de México, Centro de Ciencias de la Atmósfera
2014
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| Online Access: | http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0188-49992014000100005 |
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