Author: Herr Dr. Amoneit
Last saved by: Saritas, Sevim

Oil Content and Fatty Acid Profile of Microalgae Scenedesmus sp. and Chlorella sp. Cultivated Under Different Conditions  
Violeta Makareviciene, Virginija Skorupskaite, Aleksandras Stulginskis University, Akademija, Kaunas r., Lithuania  

Microalgae due to their fast growth, the abilities to accumulate oil, biofixate carbon dioxide, treat wastewater and not to compete with agriculture for land areas seems to be very attractive new object in order to use their biomass for biofuel production. 
The aim of research was to evaluate the influence of growing conditions on accumulation of algae Scenedesmus sp. and Chlorella sp. oil and its fatty acid composition. 
Two microalgae species that are common in the lakes of Lithuania were selected for experiments. Oil content was estimated in microalgae biomass, which was cultivated under different conditions: using liquid waste after biogas production, liquid waste + technical glycerol and BG11 medium containing 0.12, 0.06 and 0.03 gl^-1 N, BG11 (0.12 gl^-1 N) + technical glycerol. Microalgae biomass was harvested by centrifugation, dried; oil was extracted with hexane by using Soxhlet apparatus. Fatty acid composition of oil was determined by gas chromatography. The highest oil content (app.  18 %) in biomass of both algae species was estimated when algae was cultivated in liquid waste medium with 0.09 gl^-1 N and 2 gl^-1 additive of technical glycerol. Accumulative oil content in algae cells was increasing by decreasing of N concentration in growth medium. Oil content in algae Scenedesmus sp. cells varied from 1.48 % to 12 % and in Chlorella sp. cells from 3.71 % to 8.49 % by decreasing of N concentration in growth medium from 0.12 gl^-1 to 0.03 gl^-1. Evaluation of fatty acid composition of algae oil showed that Scenedesmus sp. oil contain 22.7 % and Chlorella sp. oil – 36.5 % of saturated fatty acids, the largest amount of palmitic acid was found. The content of monounsaturated acids in the oil of both algae strains was nearly the same and equaled to 46 %. The amount of oleic acid in this count was 41.9-43.1 %. Compared with rapeseed oil, investigated algal oil was not so rich in polyunsaturated fatty acids. Furthermore, it was determined that the content of linolenic acid of all investigated algae species corresponds to the requirements of the biodiesel Standard EN 14214, which states that the content of this acid in biodiesel fuel should not exceed 12 %.