Waste-free technology of wastewater treatment to obtain microalgal biomass for biodiesel production

Five axenic cultures of microalgae were isolated from the wastewater of Almaty city and identified as Chlorella vulgaris strain № 1, Chlorella sp. strain № 3, Scenedesmus obliquus, Phormidium foveolarum and Lyngbya limnetica. Among these strains, C. vulgaris strain № 1 was characterized by the maximum growth rate and the highest productivity. Mass cultivation of this strain in wastewater resulted in accumulation of 5 × 107 cells per ml in 16 days, and in the removal of ∼95% of pollutants from water. Cells of C. vulgaris consisted of ∼35% proteins, 29% carbohydrates, 30% lipids, and 6% ash, as calculated on a dry weight basis. The major fatty-acids of C. vulgaris were represented by palmitic, cis-7,10-hexadecenoic acid, linoleic, and α-linolenic acids. Culturing in wastewater decreased the unsaturation index of FAs. Thus, C. vulgaris cells are suitable for both waste water purification and accumulation of biomass for further biodiesel production.