Effects of light intensity and culture medium on the chemical composition and growth parameters of Nannochloropsis oculata and Porphyridium cruentum

Microalgae are considered sources of compounds of high nutritional value. This study determined whether 400 mu E/m(2)/s (HL) and 80 mu E/m(2)/s (LL) light intensities and algal medium (AM) and f/2 Guillard medium (f/2GM) influence kinetic parameters, moisture, ash, lipids, carbohydrate, protein, amino acid, vitamins contents of the microalgae Nannochloropsis oculata and Porphyridium cruentum. N. oculata recorded the highest cell density of 341.64 +/- 2.36 x 10(6) cells/ml under HL in AM, while P. cruentum achieved 56.60 +/- 1.33 x 10(6) cells/ml under LL in f/2GM. The highest lipids content was 28.66 +/- 0.14% for N. oculata, and 13.40 +/- 0.25% for P. cruentum, both under LL in f/2GM. The higher carbohydrates content was obtained in AM, 30.41 +/- 1.10% at LL and 47.57 +/- 1.52% at HL for N. oculata and P. cruentum respectively. The protein content was 34.53 +/- 1.33% and 26.03 +/- 1.00% both under HL in AM for N. oculata and P. cruentum respectively. In terms of amino acid and vitamins composition, only N. oculata presented high content of essential amino acids and vitamins alpha-tocopherol, beta-sitosterol and beta-carotene, based on these results, N. oculata could be recommended as a rich source of lipids, protein, amino acid and vitamin and P. cruentum for their high carbohydrate.

Automated summary

This study investigates the effect of light intensity and culture medium on the growth and nutritional composition of microalgae Nannochloropsis oculata and Porphyridium cruentum. It is found that higher light intensity and certain culture medium conditions lead to higher protein content and higher content of certain vitamins in N. oculata. On the other hand, P. cruentum shows higher carbohydrate content under lower light intensity.