PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Simultaneous Cr(VI) and lindane bioremediation by Streptomyces sp. M7: Environmental factors influence evaluation
Autor/es:
APARICIO J.; ATJIAN M.; ÁLVAREZ A; CUOZZO S.,; POLTI M.; SIMÓN SOLÁ S
Lugar:
Kusadasi
Reunión:
Simposio; ISBA17; 2014
Institución organizadora:
Elsevier
Resumen:
The co-contaminated environments with metals and organic compounds are difficult to treat because of the mixed nature of the contaminants. Lindane is an organochlorine pesticide with high persistence and toxicity. The Cr(VI) is used by several industries, and it is toxic and mutagenic. Bioremediation is a low cost technology, which could be an alternative to remove these compounds. Streptomyces sp. M7, previously isolated and characterized, showed ability to remediate soil samples co-contaminated with Cr (VI) and lindane. In this study, the effects of various environmental factors (physical, chemical and biological) on bioremediation of soils contaminated with Cr(VI) and lindane were studied using Streptomyces sp. M7, to optimize the process. Besides, the usefulness of Lactuca sativa as biomarker was evaluated. Determination of optimum inoculum concentration of Streptomyces sp. M7: Soils were contaminated with 25 mg kg-1 of lindane and 50 mg kg-1 of Cr(VI), and inoculated with Streptomyces sp. M7: 0.5; 1.0; 2.0 and 4.0 g kg-1 soil. Controls non-contaminated or uninoculated with Streptomyces sp were performed. Flasks, with 200 g of soil were incubated for 14 days at 30 °C. Residual contaminants concentrations were determined. The lowest concentration of Streptomyces sp. M7 that simultaneously allowing greater removal of Cr(VI) and lindane, in co-contaminated samples was 1 g kg-1. The influence of physical and chemical parameters on the soil bioremediation by Streptomyces sp. M7 was assessed using a full factorial design. The tested factors and levels were: Temperature: 25, 30, 35 ºC; Humidity: 10, 20, 30%; Initial concentration of Cr (VI): 20, 50, 80 mg L-1; Initial lindane concentration: 10, 25, 40 mg L-1. The model, with 4 factors, demonstrated to be suitable for studying s soil bioremediation by Streptomyces sp. M7. It was possible to predict the performance of Streptomyces sp. M7 during bioremediation, knowing the initial conditions of the system. The higher Cr(VI) removal was produced under elevated temperature and low humidity. The higher lindane removal under high Cr(VI) initial concentration and humidity. Effectiveness of both toxic removal by Streptomyces sp. M7 was evaluated using, ecotoxicity bioassays on Lactuca sativa. Germination and radicle and hypocotyl elongation were evaluated. The toxic effects were partially reversed after bioremediation process. Tested biological parameters on lettuce seedlings improved, which would indicate an effective decrease in the contaminant concentrations. These results represent a significant advance in the study of co-contaminated environments bioremediation, and the next step would be scaling the process to achieve bioremediation of large environments that suffer mixed contamination.