PENGARUH KOMBINASI CEKAMAN NITROGEN DAN FOTOPERIODE TERHADAP BIOMASSA, KANDUNGAN KUALITATIF TRIASILGLISEROL DAN PROFIL ASAM LEMAK MIKROALGA Nannochloropsis sp

Biodiesel is a promising alternative fuel obtained from plant oils and animal fats through esterification with alcohol. Nannochloropsis sp. is a high (90%) marine triacylglycerol (TAG) producing microalgae under stress conditions. Production of lipid TAG and fatty acid composition of Nannochloropsis sp. can be engineered with abiotic stress. This study aims to examine the effect of nitrogen stress and photoperiod on biomass, chlorophyll content, fatty acid profile, and qualitative content of TAG. Nannochloropsis sp. cultivated from starter cultures were then treated in variations of nitrogen stress (N100, N75, N50, N25 and N0) with bright photoperiods: dark (12:12; 16: 8 and 24: 0) as a two-factor complete randomized study design. Data retrieval of all research parameters is carried out at the final exponential stage. The results showed the interaction of the two factors did not affect the biomass of Nannochloropsis sp. but it affects the chlorophyll content of chlorophyll content P14 (N100, 16: 8) of 7.367 mg / L not significantly different from treatment P6 (N25, 24: 0) of 3.339 mg / L and treatment P15 (N100, 24: 0) of 5,665 mg / L. All treatment combinations show the TAG content qualitatively with Nile Red staining. The observation of fatty acid profiles with GCMS showed that treatment P14 (N100, 16: 8) contained more varied fatty acids compared to P1 (N0, 12:12), P2 (N0, 16: 8), P8 (N50, 16: 8) , P10 (N75, 12:12) which consists of lauric acid, hexanoic acid, palmitic acid, linoleic acid, oleic acid, stearic acid, eicosanoic acid. Keyword : Nannochloropsis sp., interaction of nitrogen stress and photoperiod, biomass, chlorophyll, fatty acid.