2014 Effects of mid-latitude westerlies on the paleoproductivity at the Atlantic margin of South Africa during the penultimate glacial cycle: evidence from coccolith Sr/Ca ratios[disponible en anglès]
2011, Journal of Industrial Microbiology and Biotechnology - ISSN: 1367-5435 - DOI 10.1007/s10295-011-1016-6
Tots els autors:
Claudio Fuentes-Grünewald, Esther Garcés, Elisabet Alacid, Nagore Sampedro, Sergio Rossi, Jordi Camp
Two different strains of microalgae, one raphidophytes and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production.
Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 µM NaNO3) than under control conditions (20°C; 880 µM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L-1 in A. minutum and 323 mg L-1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.