In the present study the production of phenolic acids and fl avonoid compounds by E. gracilis exposed to two cadmium concentrations (0.02 and 0.14 mM) was evaluated using high-performance liquid chromatography (HPLC). The results showed that E. gracilis exposed to 0.02 mM Cd +2 increased signifi cantly the total content of phenolic compounds (798.46 ± 12.61 μg GA/g) and total fl avonoids (241.34 ± 47.63 μg QE/g) with respect to the control (137.34 ± 19.80 μg QE/g DW and 549.00 ± 8.57 μg GA/g DW, respectively). However, no signifi cant increase in the total content of phenolic compounds (568.54 ± 17.42 μg GA/g DW) and total fl avonoids (141.11 ± 9.36 μg QE/g DW) were observed in E. gracilis exposed to 0.14 mM Cd +2. Further research is necessary to determine the specifi c role of fl avonoids in E. gracilis exposed to high concentrations of Cd +2 .

RESUMEN.En esta investigación se evaluó el efecto de la exposición de cobre en la capacidad de bioacumulacion de metal en células de Euglena gracilis. La acumulación de metal medida con la técnica de fluorescencia de rayos X (XRF) mostró que la acumulación de Cu +2 en E. gracilis fue dosis dependiente y se incrementó significativamente en las células tratadas con 0.4 y 0.8 mM de Cu +2 con respecto al control. No se descarta la presencia de una estrategia de acumulación en E. gracilis que podría involucrar la participación de una serie de múltiples procesos, como producción de vacuolas. Futuros estudios al respecto deberán orientarse a evaluar la capacidad de bioacumulación de E. gracilis para su aplicación en programas de biorremediación de sistemas acuáticos. Palabras clave: Euglena gracilis, XRF, cobre, contaminación, tolerancia, ecotoxicología. Assessment of copper bioaccumulation in Euglena gracilisby X-Ray fluorescence technique ABSTRACT. The effect of the exposure to copper in metal bioaccumulation capacity in cells from Euglena gracilis was evaluated in this study. Metal accumulation measured with the X-ray fluorescence (XRF) technique showed that the accumulation of Cu +2 in E. gracilis was dose dependent and was significantly increased in cells treated with 0.4 and 0.8 mM of Cu +2 with respect to control. The presence of an accumulation strategy in E. gracilis that could involve the participation of a number of multiple processes, such as production of vacuoles, is not discarded. Future studies should be oriented to evaluate the potential for bioaccumulation of E. gracilis to be applied in bioremediation of aquatic systems programs.

Corn starch is one of the most widely used biopolymers in the world for various applications, due to its high production, renewable, low cost, non-toxic, biodegradable and provide great stereochemical diversity by presenting a complex structure with unique qualities that they depend on multiple factors to obtain special properties for a specific use and/or of interest. From the synthesis of the starch granule to its extraction for its subsequent use, it promotes innovative characteristics, presenting infinite functionalities applicable and/or as a substitute for synthetic polymers. However, some limitations of hydrophilicity, thermal and mechanical properties, rapid degradability and strong intra and intermolecular bonds of the polymer chains make their use difficult in the medium and long term. Enzymatic, chemical and physical methods continue to be used today, creating by-products such as polluting waste and which can be costly. Therefore, the polymeric modification of the starch granule is necessary to mitigate limitations and by-products, currently the use of starch blends is a promising trend to produce new and innovative desirable properties. This chapter describes the advances and trends in the physicochemical properties of corn starch blends Zea mays L. as a potential material, leader for its attractive properties and benefits that it has to offer, demonstrating that when combined with other starches from different botanical sources and/or molecular structure present unique and unequaled synergisms.