The Effects of Nitrogen and Phosphorus Limitation and Infusion on Nannochloropsis oculata

The purpose of this project was to analyze the effects of nitrogen and phosphorus limitation and infusion on the oil production and biomass of Nannochloropsis oculata. This constitutes a key step toward maximizing algae lipid production for use in alternative, environmentally-friendly fuels. We hypothesized that algae grown in a nitrogen limited medium would yield the greatest amount of lipids and have the greatest mass after a nine day period of culturing. Further, the initial lipid amount (negative control) was determined through hexane extraction, yielding an average of 0.061ml oil per gram of algae. Then, two samples of N. oculata were cultured in each of the four medium types: Bristol's medium (positive control), a nitrogen limited medium, a phosphorus limited medium, and a nitrogen and phosphorus infused medium. Sample analysis showed that algae grown in the phosphorus limited medium had the highest average mass (2.4g), oil content (0.62ml), and oil content per gram (0.26ml/g). While the results rejected the hypothesis, they have still determined a medium that effectively increases algal lipid yields (phosphorus limited medium), which was one of the major goals.