EFFECT OF PHOTOPERIOD AND STRESS PHYSIOLOGICAL NUTRIENTS (N AND SI) ON THE GROWTH AND LIPID CONTENT OF MICROALGAE SKELETONEMA COSTATUMTutik Nurhidayati, Siti Nur A., Hery Purnobasuki, Endang Purwanti S. and Wirdatul Muslihatin
Skeletonema costatum is a microalgae that can be used as raw material for biodiesel. S. costatum has a relatively rapid doubling time, and a high lipid content is 7.42% dry weight. Microalgae lipid accumulation increased in drought stress. This study aimed to determine the effect of photoperiod and physiological stress nutrients N and Si on growth and lipid content S. costatum. The method used is a culture of S. costatum in physiological media stress nutrient N and Si with variations of photoperiod. Cell density measurements every 6 hours using Haemocytometer Improved Neubauer. Harvesting is done at the end of the exponential phase. The parameters measured were the growth curve, biomass and lipid levels. Data were analyzed using two-way ANOVA. The results showed that growth is highest in the treatment of A24 with a cell density of 132 500 cells/ml and 0.49 gram of biomass, while the highest lipid levels in the treatment of B24 by 14.42%.