Acyl lipid composition variation related to culture age and nitrogen concentration in continuous culture of the microalga Phaeodactylum tricornutum.

The influence of culture age and nitrogen concentration on the distribution of fatty acids among the different acyl lipid classes has been studied in continuous cultures of the microalga Phaeodactylum tricornutum. The culture age was tested in the range of 1.15-7 days, controlled by adjusting the dilution rate of fresh medium supplied. The effect of nitrogen concentration was tested from saturating conditions to starvation by modifying nitrate concentration in the fresh medium. Culture age had almost no influence on the fatty acid content; 16:0, 16:3 and 20:5 increased moderately wherein the level of 16:1 decreased when the culture age decreased. Culture age had no effect on the total fatty acid content that remained around 11% of dry weight. Conversely, culture age had a greater impact on lipid classes, producing changes in amounts of triacylglycerols (TAG) which ranged between 43% and 69%, and galactolipids (GLs) that oscillated between 20% and 40%. In general, the content of polar lipids of the biomass decreased with culture age. The other factor assayed, nitrogen content, affected the fatty acid profile. Saturated and monounsaturated fatty acids accumulated when the nitrogen concentration was decreased. The experiments regarding the effect of nitrogen concentration on lipid species were carried out with cells of an average age of 3.5 days. A decrease of the nitrogen concentration caused the GL fraction to decrease from 21 to 12%. Conversely, both neutral lipids (NLs) and phospolipids (PLs) increased from about 73 to 79% and from 6 to 8%, respectively. In these experiments, TAG was the lipid class with the highest increase, from 69 to 75%.

[1]  Peter Pohl,et al.  Biomass production, total protein, chlorophylls, lipids and fatty acids of freshwater green and blue-green algae under different nitrogen regimes☆ , 1984 .

[2]  K. Reitan,et al.  EFFECT OF NUTRIENT LIMITATION ON FATTY ACID AND LIPID CONTENT OF MARINE MICROALGAE 1 , 1994 .

[3]  R. Siron,et al.  Changes in the fatty acid composition of Phaeodactylum tricornutum and Dunaliella tertiolecta during growth and under phosphorous deficiency. , 1989 .

[4]  E. Belarbi,et al.  Acyl lipids of three microalgae , 1998 .

[5]  M. A. Cobelas.  Lipids in microalgae. A review, 2: Environment. , 1989 .

[6]  E. Molina Grima,et al.  A mathematical model of microalgal growth in light-limited chemostat culture , 1994 .

[7]  C. Parrish,et al.  Particulate and dissolved lipid classes in cultures of Phaeodactylum tricornutum grown in cage culture turbidostats with a range of nitrogen supply rates , 1987 .

[8]  P. Pohl,et al.  Formation of biomass, total protein, chlorophylls, lipids and fatty acids in green and blue-green algae during one growth phase.☆ , 1984 .

[9]  P. Mazliak,et al.  Lipid composition of Euglena gracilis in relation to carbon-nitrogen balance , 1995 .

[10]  F. G. Fernández,et al.  Outdoor culture of Isochrysis galbana ALII-4 in a closed tubular photobioreactor , 1994 .

[11]  P. Pohl,et al.  Fatty acids and lipids of marine Algae and the control of their biosynthesis by environmental factors , 1979 .

[12]  I. Gustafsson,et al.  FATTY ACID CONTENT AND CHEMICAL COMPOSITION OF FRESHWATER MICROALGAE 1 , 1992 .

[13]  Malcolm R. Brown,et al.  EFFECTS OF HARVEST STAGE AND LIGHT ON THE BIOCHEMICAL COMPOSITION OF THE DIATOM THALASSIOSIRA PSEUDONANA 1 , 1996 .

[14]  H. A. Hoppe,et al.  Marine algae in pharmaceutical science , 1979 .

[15]  J. Harwood,et al.  Lipid biochemistry , 2020, Springer US.

[16]  M. V. Bell,et al.  Lipid composition during growth of motile and coccolith forms of Emiliania huxleyi , 1996 .