Influence of temperature and nutrient content on lipid production in freshwater microalgae cultures

Abstract

The production of biomass by microalgae is considered a clean alternative compared to other plant crops that require large areas for cultivation and that generate environmental impacts. This study evaluated the influence of temperature and nutrients on lipid contents of cultured species of freshwater microalgae, with a view toward using these lipids for biodiesel production. Two strains of Monoraphidium contortum, a culture containing Chlorella vulgaris and Desmodesmus quadricauda and another strain of Microcystis aeruginosa were maintained in the laboratory for six days, in five culture media: modified ASM-1 (control, with high concentrations of phosphate and nitrate; phosphorus-deficient; non-limiting phosphate; nitrogendeficient; and non-limiting nitrate). The cultures were then exposed to temperatures of 13°C, 25°C (control) and 37°C for eight days (n=3). Lipids were extracted by the cold-solvent (methanol and chloroform) method. On average, the highest total lipid yields were observed when the strains were maintained at 13°C and in the non-limiting nitrate medium. The lipid percentage varied depending on the concentration of algal biomass. This study showed that manipulation of controlling factors can increase the lipid concentration, optimizing the total production in order to use this raw material for biodiesel.

Cultural Conditions and Nutrient Composition as Effective Inducers for Biomass and Lipid Production in Fresh Water Microalgae

“…Among the varying culture conditions, temperature affects the lipid accumulation in microalgal cells. Microalgae respond to decreased growth temperature by increasing the ratio of unsaturated to saturated fatty acids and highest total lipid was observed at lower temperatures (Bohnenberger and Crossetti, 2014;Cao et al, 2014;Hoffmann et al, 2010). In this study, 15.2% increase in lipid production was observed at 25°C when compared to 20°C, which is in accordance to Converti et al (2009), where increase of the cultivation temperature from 20-25°C has increased the lipid content.…”

Physiological Changes of Parachlorella Kessleri TY02 in Lipid Accumulation under Nitrogen Stress

“…The mixture was then centrifuged at 5000 rpm min −1 for 10 min and the precipitate liquid was retained. After repeating the above steps twice and combining all the liquids in a 5-mL glass bottle, the mixture was blown dry with nitrogen and then weighed [26]. The total lipid content and lipid productivity were calculated according to the following formula: LC(%)=(normalw3−normalw2)/normalw1×100%where LC (%) is the weight percentage of the total lipid in the algal powder, w1 (g) is the dry weight of the algal powder, w2 (g) is the weight of empty bottle, and w3 (g) is the total weight of the algal lipids and the glass bottle after the algal lipids were extracted in Equation (7).…”

The effect of physicochemical conditions and nutrient sources on maximizing the growth and lipid productivity of green microalgae

“…Interestingly, for Dunaliella tertiolecta cultured under nutrient sufficient conditions, a higher growth rate was achieved at 20°C, while cultivation at 10°C led to higher lipid accumulation (Roleda et al ). In the case of Monoraphidium contortum , Chlorella vulgaris and Desmodesmus quadricauda optimal growth and lipid accumulation were obtained at 13°C temperature (compared with 25 and 37°C), combined with non‐limiting nitrate supply (Bohnenberger & Crossetti ). On the other hand, the optimum temperature for Chlorella sp.…”