Light, temperature and nitrogen starvation effects on the total lipid and fatty acid content and composition ofSpirulina platensis UTEX 1928

Abstract

The total lipid and fatty acid content of Spirulina platensis UTEX 1928 was 7.2 and 2.2% respectively of cellular dry weight under controlled conditions supporting high growth rates. With increases in irradiance from 170 to 870 umol photon m-2 s -', growth rate increased, total lipid decreased, and fatty acid composition was unaffected. At 1411 #mol photon m -2 s -1, total lipid increased slightly and percent composition of the fatty acid gamma linolenic acid increased.Growth and total lipid content of S. platensis were affected by changes in growth temperature from 25 to 38 °C. With increased growth rate, total lipid content increased. This suggests that the storage of carbon increases at temperatures supporting high growth rates. The degree of saturation increased with temperature. Although the percent composition of gamma linolenic acid was higher at lower growth temperature, production was still primarily a function of growth rate. The effect of temperature on fatty acid content and degree of saturation was of secondary importance.Nitrogen starvation increased total lipid content but decreased fatty acid content as a percentage of dry weight; composition of the fatty acids was unaffected. N-starvation appeared to suspend synthesis of long chain fatty acids in S. platensis, suggesting that some other compound stores fixed carbon when nitrogen is limiting.It was concluded that fatty acid production in S. platensis is maximized by optimizing culture conditions for growth.

Influence de la température, de l'intensité lumineuse et du stade de croissance sur la composition biochimique deChlorella sorokinianaShihira & Krauss

“…Parmi les facteurs affectant les proportions en lipides chez les microalgues, on peut citer : -la température (Aaronson 1973, Tedesco & Duerr 1989, Tan & Johns 1991, -l'intensité lumineuse (Sukenik et al 1989, Tedesco & Duerr 1989, Harrison et al 1990, Renaud et al 1991, -la photopériode (Shifrin & Chisholm 1981), -la concentration en C0 2 du milieu de culture (Becker & Venkatamaran 1980), -la concentration et la nature de la source azotée (Shifrin & Chisholm 1980, Kost et al 1984, Thomas et al 1984a,b, Ben-Amotz et al 1985, Harrison et al 1990, Chen & Johns 1991, -la concentration en silice, dans le cas des Diatomées (Shifrin & Chisholm 1981), -la pression osmotique du milieu (Ben-Amotz et al 1985, Al Hassan et al 1990 -le stade de croissance (Dubinsky et al 1978, Piorreck et al 1984, Barclay et al 1985.…”

La vidange d'un grand réservoir considérée comme une expérience de biomanipulation. Premiers résultats : contrôle exercé par les poissons sur la structure et la composition biochimique du plancton

“…Les teneurs en lipides évaluées chez quelques algues maintenues en culture varient en fonction de l'espèce, de son stade de développement et des conditions de culture (Tedesco & Duerr 1989, Harrisson et al 1990, Chen & Johns 1991, Sicko-Goad & Andresen 1991. Concernant le zooplancton, les lipides constituent une importante réserve énergétique.…”

Growth and fatty acid profiles of microalgae species isolated from the Baja California Peninsula, Mexico

“…Fatty acid content differed between cyanophyte groups -the filamentous group had high α-linolenic acid content (13.4 to 37.5%), consistent with other studies (Zepka et al, 2007;Sharathchandra & Rajashekhar, 2011;Opris et al, 2013). Whereas Aphanocapsa marina (colonies of spherical cells) had a high percentage of palmitoleic acid (44.1%), this might be linked to their membrane lipid composition (Tedesco & Duerr, 1989;Sato & Wada, 2009). …”