Biodiesel production from microalgae triacylglycerols is growing, because this feedstock is a more sustainable and advantageous alternative. In this study, we isolated and identified fourteen strains of native microalgae from the Peruvian Amazon. These strains showed great heterogeneity in biomass productivity, lipid productivity and lipid content, and thus, three of them (Acutodesmus obliquus, Ankistrodesmus sp. and Chlorella lewinii) were selected for further evaluation under culture of nitrogen-sufficient (+N) and nitrogen-deficient (−N) Chu medium No. 10. These microalgae species showed modifications in biomolecule content (protein, lipid and carbohydrate) with a pronounced increase of lipids and carbohydrate and a decrease of protein content under stress culture. Furthermore, the fatty acid profile was peculiar for each species, and these patterns showed evident changes, particularly in the proportion of saturated and monounsaturated fatty acids. The results of this research suggest that the isolated native microalgae, from the Peruvian Amazon, could be suitable candidates for biodiesel production.

No abstract

-40). Las evaluaciones biométricas muestran que mayor crecimiento, conversión alimentaria y factor de condición se obtuvieron en A. scapularis alimentadas con la dieta DM-48 (P < 0,05). Sin embargo, la relación talla-peso y consumo de alimento-talla fueron similares entre los tratamientos dietarios. Por otro lado, menores concentraciones de proteína y mayores de lípidos se obtuvieron en el músculo de juveniles de A. scapularis alimentados con las dietas DM-48 y DF-50 (P < 0,05), respectivamente. El análisis de componentes principales mostró una mayor correlación entre peces alimentados con la dieta DM-48 y el contenido muscular de DHA, EPA y ARA; y con el crecimiento. Los resultados sugieren que la formulación de alimentos para juveniles de A. scapularis debería contemplar al menos de 48% de proteína y concentraciones importantes de DHA, EPA y ARA para su adecuado crecimiento de esta especie. Palabras clave: Anisotremus scapularis, Haemulidae, chita, ácidos grasos esenciales, maricultura.Evaluation of commercial diets on growth and its effect on muscle biochemical composition of juvenile Peruvian grunt, Anisotremus scapularis (Tschudi, 1846) (Familia: Haemulidae)ABSTRACT. The growth, muscle proximal composition and fatty acid profile of juveniles of Anisotremus scapularis fed with four commercial diets were evaluated. During 106 days, 200 fishes, were distributed in four treatments, fish were fed with commercial diets identified by their protein content: 50% (DF-50), 48% (DM-48), 44% (DT-44) and 40% (DT-40). Biometric evaluations showed that higher growth (P < 0.05), feedconversion and condition factor were obtained in A. scapularis fed with DM-48. However, both length-weight and food intake-size relationships were similar among dietary treatments. Lower (P < 0.05) protein and higher (P < 0.05) lipid concentrations in muscle of A. scapularis fed with DM-48 and DF-50 were obtained, respectively. Principal component analysis showed a higher correlation between fishes fed with DM-48 and DHA, EPA, and ARA muscle contents as with growth. Our results suggest that the food formulation for juveniles of A. scapularis should include at least 48% protein and significant concentrations of DHA, EPA and ARA for a proper growth of this species.

La metodología analítica implementada para la cuantificación de proteínas en la microalga Arthorspira platensis por espectrofotometría UV-Vis fue el método de Hartree-Lowry. Para lograr este objetivo, se optimizaron los factores de extracción de proteínas por el método estadístico de diseño de superficie de respuesta de Box Behnken y se obtuvieron lossiguientes resultados de los parámetros implementados: la linealidad, donde se reportó un coeficiente de determinación (R2 ) mayor a 0,995, en el estudio de repetibilidad un coeficiente de variación menor al 2 %, un porcentaje de recuperación entre 94 % y 101 %, los límites de detección y cuantificación fueron 2,36 µg/mL y 7,86 µg/Ml, respectivamente y el estudio de la robustez demostró que el método analítico tuvo mayor sensibilidad al cambio del peso de la muestra y al cambio del volumen de reactivo C respecto al resto de factores evaluados.

The purpose of this study was to evaluate the effect of time in culture on fatty acid composition of copepods Tisbe sp. and Apocyclops sp. For experiments, Tisbe and Apocyclops copepodites were separated and placed in 4‐L containers at 5 ind/mL. The fatty acids were evaluated at three different periods (hours) of culture (treatments): T1 = 6 hr, T2 = 12 hr, and T3 = 168 hr. Culture conditions were 25°C, salinity 35 ppt, illuminance 2,500 lx, with gentle aeration. The live food was Isochrysis galbana at 75 × 103 cells/mL. A total of 14 fatty acids were detected for both copepods. Although, there were absent two fatty acids for Apocyclops sp. (C18:3n‐6 and C18:1n‐7). The major percentages of fatty acids were more than 50% of polyunsaturated fatty acids. The essential fatty acids were detected such as C22:6n‐3 (docosahexaenoic acid [DHA]), C20:5n‐3 (eicosapentaenoic acid [EPA]), and C20:4n‐6 (arachidonic acid) for both species. Tisbe sp. was the species which shows the highest quantity of total lipids compared to Apocyclops sp. for the three treatments. Besides, in T3 both species had greater quantities of total lipids in respect to the first treatment. The ratio of DHA/EPA was optimal for culture of fish marine larvae because the proportion is higher than 2:1.