Investigation of the Growth rate and Fatty acids profile of microalgae Chlorella vulgaris reared in culture medium containing urban sewage

This research aimed to measure the fatty acids content of Cholorella vulgaris reared in different culture media containing urban sewage. Four treatments (each with three replicates) containing different ratios of urban sewage and f/2 culture medium were prepared,and kept in the laboratory condition. The microalgae cells were separated by centrifugation at different stages of the experiment. The growth rate and fatty acids profile of all treatments were measured. The results showed that treatments 1 and 4 had the highest growth rate. Among all the treatments the highest fatty acid content were those of 0:C17 (Heptadecanoic acid) and 0:C6 (Hexanoic acid), and the highest amount of unsaturated fatty acids with a single double bond belonged to 1:C16 (Palmitoleic acid) and C18:1Cis9 (Oleic acid). Significant differences (p<0/05) were observed between the monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) of all treatments. The results of ANOVA on the effects of the culture medium on the Omega-3 (ω−3) and Omega-6 (ω−3) content revealed significant differences (p<0/05) between all treatments. The highest ω−3 content was recorded in treatment 2 (18.28%), whereas in the other treatments it was less than 2%. The highest value of ω−6 was recorded in treatments 2 and 4. Based on the results of this research, we recommend that urban sewage can be utilized as a substitute culture medium for the growth and mass production of C. vulgaris microalgae as a rich sources of fatty acids especially ω−3.