Growing global energy demand requires the development of novel alternatives for sustainable energy production and microalgae are being widely studied as an attractive source of biofuels and bioproducts. To obtain oil from microalgae biomass, pre-treatment methods are important for the product quality and production cost. In this work, lipids from microalgae Amphiprora sp. were obtained 842 Ángel Darío González-Delgado et al. using acid hydrolysis-solvent extraction route. The effect of hydrolysis and solvent extraction times on lipid extraction efficiency were evaluated in order to determine the most suitable conditions for performing both stages. In addition, morphological response of biomass after acid hydrolysis and liquid extraction was studied, as well as lipid and metabolites characterizations. The highest lipid efficiency (38.74%) was reached at 120 minutes of hydrolysis time and 16 hours of lipid extraction. The cell disruption was confirmed through the presence of remnants of cellular wall and cytoplasmic constituents and changes in colour of microalgae corresponded to alterations in cellular membrane caused by solvent extraction. The low percentage of saturated fatty acids (20.9 %) indicated that Amphiprora sp. is less suitable for biodiesel production in comparison with other genus widely studied for lipid extraction.

The rapid growth of human population and technological advances have led to an urgent need for alternative sources of renewable energy and microalgae have attracted much global attention in recent years. In this work, production of oil and reducing sugars from microalgae Navicula sp. were studied through the design and experimental evaluation of two sequential routes based on pre-treatments (acid hydrolysis and organosolv) and lipid extraction. The effect of these procedures on microalgae cell structure was evaluated through changes in morphology of this biomass. For Organosolv-Soxhlet extraction route, lipid efficiency was 46.96%, 852 Ángel González-Delgado et al. higher than for acid hydrolysis-Soxhlet extraction route (39.98%) that is attributed to a greater degree of cell lysis due to the operating conditions of Organosolv pretreatment. In addition, total reducing sugar (RS) measurement corresponded to 0.45 and 1.47 mg/mL for acid hydrolylisis and organosolv, respectively, which result significatly affected by contact time of biomass with disruptor agents. From characterization of oil extracted, content of saturated fatty acids was 45.1%, this value indicates that Navicula sp. is suitable as feedstock for biofuel production and Organosolv-Soxhlet extraction could be applied as an efficient route for this purpose.

Microalgae have emerged as environment friendly alternative source of valuable products for energy, pharmaceutical and cosmetic industries. These microorganisms have been also studied in wastewater treatments due to its ability to remove CO2, nitrogen, phosphorus, and toxic metals. In this work, cultivation of microalgae Chlorella vulgaris was carried out in aquaculture wastewater in order to reduce its contents of NO3 and PO4. In addition, different concentration of inorganic 94 Estefany Blanco-Carvajal et al. carbon sources (NaHCO3 and Na2CO3) and addition times were considered for determining suitable conditions in microalgae culture to produce proteins. It was found that highest protein content (45 % w/w) was achieved at 3.4 g/L of NaHCO3 and 19 h of addition time.

El presente trabajo de investigación tiene como objetivo determiner el efecto de la relación Carbono/Nitrógeno en la producción de biomasa y carotenoides totales en una cepa de Scenedesmus sp. Inicialmente, se evaluaron tres fuentes de carbono diferentes (carbonato de sodio, bicarbonato de sodio y acetato de sodio) bajo diferentes concentraciones de una fuente de nitrógeno (nitrato de sodio) en reactores tubulares de 250 ml. Los reactores fueron operados a 25°C durante 40 días en un ciclo de luz:oscuridad de 12:12 horas y un flujo continuo de aire. De acuerdo con los resultados se encontró que mediante el ajuste de la concentración de la fuente de carbono y nitrógeno, es posible aumentar la concentración de biomasa hasta 0.8 g/L. Por otra parte, mediante la regulación de la concentración de carbonato de sodio y nitrato de sodio, el contenido final carotenoides totales se incrementó dos veces (de 0.3 a 0.66% p/p). Los resultados de este estudio muestran que, al ajustar las concentraciones de la fuente de carbono y de nitrógeno es posible obtener un aumento interesante en la biomasa final y la concentración de carotenoides totales. Finalmente, es importante resaltar que se debe estudiar el efecto de otras estrategias como la luz, la salinidad y el pH, junto con la relación C/N para obtener un método adecuado que lleve a las celulas hacia un estress metabolico y mejore así la síntesis de carotenoides en Scencedesmus sp.

El presente trabajo de investigación tiene como objetivo determiner el efecto de la relación Carbono/Nitrógeno en la producción de biomasa y carotenoides totales en una cepa de Scenedesmus sp. Inicialmente, se evaluaron tres fuentes de carbono diferentes (carbonato de sodio, bicarbonato de sodio y acetato de sodio) bajo diferentes concentraciones de una fuente de nitrógeno (nitrato de sodio) en reactores tubulares de 250 ml. Los reactores fueron operados a 25°C durante 40 días en un ciclo de luz:oscuridad de 12:12 horas y un flujo continuo de aire. De acuerdo con los resultados se encontró que mediante el ajuste de la concentración de la fuente de carbono y nitrógeno, es posible aumentar la concentración de biomasa hasta 0.8 g/L. Por otra parte, mediante la regulación de la concentración de carbonato de sodio y nitrato de sodio, el contenido final carotenoides totales se incrementó dos veces (de 0.3 a 0.66% p/p). Los resultados de este estudio muestran que, al ajustar las concentraciones de la fuente de carbono y de nitrógeno es posible obtener un aumento interesante en la biomasa final y la concentración de carotenoides totales. Finalmente, es importante resaltar que se debe estudiar el efecto de otras estrategias como la luz, la salinidad y el pH, junto con la relación C/N para obtener un método adecuado que lleve a las celulas hacia un estress metabolico y mejore así la síntesis de carotenoides en Scencedesmus sp.