Lipids rich in ω-3 polyunsaturated fatty acids from microalgae

Abstract

Despite microalgae recently receiving enormous attention as a potential source of biodiesel, their use is still not feasible as an alternative to fossil fuels. Recently, interest in microalgae has focused on the production of bioactive compounds such as polyunsaturated fatty acids (PUFA), which provide microalgae a high added value. Several considerations need to be assessed for optimizing PUFA production from microalgae. Firstly, a microalgae species that produces high PUFA concentrations should be selected, such as Nannochloropsis gaditana, Isochrysis galbana, Phaeodactylum tricornutum, and Crypthecodinium cohnii, with marine species gaining more attention than do freshwater species. Closed cultivation processes, e.g., photobioreactors, are the most appropriate since temperature, pH, and nutrients can be controlled. An airlift column with LEDs or optical fibers to distribute photons into the culture media can be used at small scale to produce inoculum, while tubular and flat panels are used at commercial scale. Depending on the microalgae, a temperature range from 15 to 28 °C and a pH from 7 to 8 can be employed. Relevant conditions for PUFA production are medium light irradiances (50-300 μmol photons m(-2) s(-1)), air enriched with (0-1 % (v/v) CO2, as well as nitrogen and phosphorous limitation. For research purposes, the most appropriate medium for PUFA production is Bold's Basal, whereas mixotrophic cultivation using sucrose or glucose as the carbon source has been reported for industrial processes. For cell harvesting, the use of tangential flow membrane filtration or disk stack centrifugation is advisable at commercial scale. Current researches on PUFA extraction have focused on the use of organic solvents assisted with ultrasound or microwaves, supercritical fluids, and electroporation or are enzyme assisted. Commercial-scale extraction involves mainly physical methods such as bead mills and expeller presses. All these factors should be taken into account when choosing a PUFA production system, as discussed in this review.

Characterization of Chlorella sorokiniana growth properties in monosaccharide-supplemented batch culture

“…Large-scale cultivation of oil crops is limited, however, by low oil yields and competition with agricultural land. Microalgae are theoretically more promising bioenergy resources offering significant advantages, such as fast growth [ 4 ], short growth cycles, high lipid yields [ 5 ], bioactive compounds production [ 6 ] and the ability to grow on non-crop lands and in salt water [ 7 – 11 ] or waste water [ 12 ]. While primary technologies involving microalgae cultivation and lipid extraction have already been established [ 13 ], low yields and high bioenergy costs are key bottlenecks to industrial-scale exploitation of microalgae.…”

Evaluación Del Perfil De Ácidos Grasos De Isochrysis Galbana Mediante El Uso De Métodos Ácidos Y Alcalinos De Transesterificación

“…Estos resultados demuestran que al ser la extracción directa la más efectiva para extraer mayor cantidad de AG desde la microalga, el proceso es más rápido y económico en cuanto a la utilización de solventes. Sin embargo, de acuerdo a lo descrito por Fukuda et al, (2001);Santos-Sánchez et al, (2016), la transesterificación alcalina es más rápida que la ácida. Sin embargo, los métodos MTD-AL2 y MTI-AL2 fueron los que menos concentraciones de AGM alcanzaron, aunque la proporción de DHA fue del 12 % en el caso de MTI-AL2.…”

“…Aunque fue el caso con mayor abundancia de todos no implicó el hecho de que fuera el que mayor cantidad obtuviera, puesto que hubo un 0,28 % de AGM respecto a biomasa seca. De esta manera, el método MTD-AL1 fue no solo el que mejor resultado obtuvo de AGM, sino también el mejor con respecto a la abundancia relativa de DHA, siendo inferior a lo descrito por Santos-Sánchez et al (2016), llegando a alcanzar 5,9 % de DHA. El método MTD-AL1 presentó la mayor eficacia con un 93,03 % seguido por MTI-AC1 con un 87,61 %.…”

“…Es por esto, que se han buscado otras fuentes alternativas como lo son las microalgas, descritas entre otras, por llegar a contener intracelularmente entre un 20 a un 50 % de su peso seco de lípidos. Incluso, bajo condiciones de estrés pueden llegar a alcanzar hasta el 85 % de producción de estos mismos (Chisti, 2007;Santos-Sánchez et al, 2016). Se describe en algunas especies que entre el 37 al 45 % de su peso puede ser contenido exclusivo de DHA (Santos-Sanchez et al, 2016).…”

Non-steroidal anti-inflammatory drugs initiate morphological changes but inhibit carotenoid accumulation in Haematococcus pluvialis

“…chrysophytes, diatoms, dinoflagellates and green algae). The economic role of certain types of cysts is unquestionable, since the production of several valuable biomolecules is connected to the resting stages of different algae [1,2]. Astaxanthin, the red ketocarotenoid is one of the highvalue microalgal products of the future, mainly because it has higher antioxidant activity than most of the known hydrophobic antioxidants [3].…”