Main content area

Stress-induced changes in pigment and fatty acid content in the microalga Desmodesmus sp. Isolated from a White Sea hydroid

Solovchenko, A. E., Chivkunova, O. B., Semenova, L. R., Selyakh, I. O., Shcherbakov, P. N., Karpova, E. A., Lobakova, E. S.
Russian journal of plant physiology 2013 v.60 no.3 pp. 313-321
Algae, absorption, acclimation, carotenoids, cell suspension culture, chlorophyll, fatty acid composition, inoculum density, light intensity, linolenic acid, microalgae, nitrogen, oleic acid, photosynthetically active radiation, starvation
Effects of light intensity, nitrogen availability, and inoculum density on growth and the content of esterified fatty acids (FA), chlorophylls, and carotenoids in Desmodesmus sp. 3Dp86E-1 chlorophyte alga isolated from the White Sea hydroid Dynamena pumila L. were investigated. The growth of algae in the complete BG-11 medium was not limited by irradiances up to 480 μE/(m² s) PAR but depended on the inoculum density. Under nitrogen starvation conditions, high-intensity light retarded growth of the microalga; this effect was less pronounced in the cultures initiated at high inoculum densities. The highest FA percentage in biomass (30% at the 3rd day of cultivation) was detected in nitrogen-starving cultures grown under high light conditions; however, the highest volumetric FA content (0.25 g/L) was attained on a complete medium at 480 μE/(m² s). An increase in the content of oleic acid (18:1) on the background of a decrease in linolenic acid (18:3) was characteristic of the microalga under stress conditions. The microalga was found to be non-carotenogenic. Nitrogen starvation brought about a dramatic decrease in chlorophyll content on the background of relatively constant carotenoid content. On nitrogen-deplete medium, the high light did not trigger the adaptive response of the pigment apparatus. The changes in absorption spectra of Desmodesmus sp. 3Dp86E-1 cell suspensions reflected the increase in relative contribution of carotenoids to light absorption by the microalgal cells; these changes were tightly related with FA accumulation. The mechanisms of acclimation of Desmodesmus sp. 3Dp86E-1 to high light and nitrogen starvation are discussed in view of possible biotechnological applications of this alga.