Evaluation of the genotoxic potential of reactive black 5 solutions subjected to decolorizing treatments by three fungal strains.

The genotoxic potential of solutions of the textile dye "Reactive Black 5" that were subjected to decolorizing treatments with the fungal strains Coriolopsis polyzona MUCL33483, Penicillium sp. MUBA001 and Pycnoporus sp. MUBA002 was tested. The genotoxicity of the solutions was determined by evaluation of micronuclei formation in Vicia faba root cells and calculation of a damage index (MN(ID)). Non-treated Reactive Black 5 solutions (50-1000 ppm) caused a statistically significant increase in micronuclei formation and, by then, in damage index. Solutions of dye treated with C. polyzona MUCL33483 and Pycnoporus sp. MUBA002 showed color loss, probably due to enzymatic breakdown of the colorant, but maintenance or even an increase in genotoxicity. On the other hand, the Penicillium sp. strain MUBA001 caused decolorization of the dye, apparently by adsorption on mycelia, and, for solutions that initially contained 50 ppm of colorant, an elimination of the genotoxicity was observed after three weeks of treatment.

Produccion de beta-glucosidasas por cultivos de bacterias termofilas indigenas del altiplano boliviano / beta-Glucoside production by thermophilic bacteria indigenous the bolivian altiplano culture

Las beta-glucosidasas son enzimas que poseen actividad hidrolitica y transferasa o transglucosidasa. Tienen diversas aplicaciones; en la biosintesis de oligosacaridos, produccion de etanol utilizando residuos agricolas y en la industria de vinos. La aplicacion industrial, sin embargo, requiere estabilidad a temperaturas elevadas, por lo que los microorganismos termofilos tienen gran interes. El proposito de esta investigacion es el de optimizar el medio de cultivo anaerobio de bacterias termofilas, para aumentar la produccion de beta-glucosidasas. Esta enzima es producida por tres aislados bacterianos: FT3, 2B y P5 los cuales fueron aislados de la region andina de Bolivia. El aislado bacteriano FT3 mostro una actividad beta-glucosidasa de 0,35 [UI/mL]. Se tomaron como variables dentro de la optimizacion del medio de cultivo las fuentes de nitrogeno y de carbono, y el pH. Asi tambien se probaron dos sistemas de cultivo: celulas libres y encapsuladas. Empleando extracto de levadura como fuente de nitrogeno se obtuvo una actividad de 0,52 [UI/mL]. En la optimizacion del pH del medio de cultivo se obtuvo una actividad de 0,81 [UI/mL] a pH 5. Como fuente de carbono se eligieron los hidrolizados de paja de trigo y paja de quinoa lleg¨¢ndose a obtener actividades de 1,27 y 1,34 [UI/mL] respectivamente. Se establecio que la localizacion celular de la enzima beta-glucosidasa es extracelular y presenta estabilidad hasta una temperatura de 80 ºC y un pH de 7.

The beta-glucosidases possess hydrolytic and transferase activity or transglucosidase. They have various applications; such as biosynthesis of oligosaccharides, production of ethanol using agricultural residues and wine industry. However for industrial application, stability to high temperatures is needed. Therefore a great interesting in the thermophile microorganism study exist. The purpose of this research is to optimize the culture medium of thermophilic anaerobic bacteria to increase the production of beta-glucosidase. This enzyme is produced by three isolate bacterial FT3, 2B and P5 which were isolated from the Andean region of Bolivia. FT3 isolate showed beta-glucosidase activity of 0.35 [IU/mL]. In regards to the optimization of culture medium variables such as nitrogen source, carbon source and pH were taken into account and also the combination with free and encapsulated bacterial cells. Yeast extract was the selected source of nitrogen obtaining an activity of 0.52 [IU/ mL]. The optimal pH was 5 obtaining an activity of 0.81 [IU/mL]. The selected carbon source was the hydrolyzed wheat straw and quinoa straw obtaining activities of 1.27 and 1.34 [IU/mL], respectively. The cellular localization of beta-glucosidase enzyme is extracellular and provides stability to temperature of 80 ºC and stability at pH 7.

Isolation and characterization of a white rot fungus Bjerkandera sp. strain capable of oxidizing phenanthrene.

Strain BOL13 was selected from 18 fungal strains isolated from an oil-spill contaminated site in Oruro, Bolivia. It was identified as a basidiomycete with high homology to Bjerkandera. The fungus degraded 100 mg phenanthrene l(-1) at 0.17 mg l(-1) d(-1) at 30 degrees C at pH 7. During phenanthrene degradation, a maximum manganese peroxidase activity of 100-120 U l(-1) was measured after 10 days of incubation. The ability of Bjerkandera sp. to produce lignin-modifying enzymes and to oxidize phenanthrene under various pH and temperature conditions was confirmed.