Effect of Light on Lipid and Fatty Acid Composition of Cyanobacteria, Anacystis nidulans (Synechococcus)

Abstract

Pigment alterations could be obtained by exposing Anacystis cultured under low white light (0.6 X 10 3 µW/cm 2 ) to high white light (3 X 10 4 µW/cm 2 ) or high red light (2 X 10 4 µW/cm 2 ). The amounts of total pigments and acyl lipids decreased from red light to high white light grown cells. Within the different cultures a relative constant proportion of lipid soluble pigments and acyl lipids could be observed. Regarding to the influence of culture conditions on the composition and percentage distribution of individual aryl lipids no effect on SQDG could be noted but high light irrespective of light quality leads to a slight -decrease in PG content. Galactolipids and the MGDG/DGDG-ratio proved to be dependent on the chosen illumination. High red light yielded in an increase in MGDG synthesis, while high white light dependent lipid decrease was lesser for DGDG than for all other lipids. In high white light grown cultures a glycolipid, not yet reported to occur in Anacystis nidulans or other cyanobacteria was detected. Concerning the fatty acid composition, this lipid shows the lowest degree of desaturation of all lipids investigated. The sugar moiety of this unknown lipid is still to be researched. Common for all cultures the galactolipids can be divided from SQDG and PG in the percentage distribution of their faty acids. C 16 : 0 , C 16 : 1 and C 18 : 1 as major components in all lipids show little to, no difference in percentage distribution between cyanobacteria grown in low white and high red light. High white light led to a relative higher amount of C 16 : 0 and C 18 : 1 in all acyl lipids, whereas C 18 : 1 correspondingly decreased. As minor fatty acid components in lipids of all cultures C 14 :0 C 14 : 11 C 17 :15 C 18 : 0 and C 20 : 0 were observed.