A 2009 study by Converti et al. studied two species of microalgae: Nannochloropsis oculata and Chlorella vulgaris. Both are considered phytoplankton. These algae range in size from 2 micrometers to 4 micrometers and are photosynthetic, eukaryotic microorganisms. Their lipid content serves as a source for biodiesel. Temperature and nitrogen concentration typically play a vital role in the growth and production of plants and photosynthetic life forms. The two species were grown at a central temperature for a control; other tests were run at 5ْْ C. above and 5ْ C. below the middle temperature. Nannochloropsis oculata had a central temperature of 20ْ while Chlorella vulgaris had a central temperature of 30. An additional temperature experiment was performed on C. vulgaris at 38 degrees Celsius. Lipid production of N. oculata was tested at 0.300 gL-1, 0.150 gL-1, and 0.075 gL-1 of nitrogen. Lipid production of C. vulgaris was tested at nitrogen concentrations of 1.50 gL-1, 0.750 gL-1, and 0.375 gL-1. N. oculata lipid content virtually doubled (7.9 % to 14.92%) with the 5 degree increase from 20 to 25; C. vulgaris lipid content dropped from 14.71% to 5.90% with the temperature change from 25 to 30 degrees. Conversely, a 75% decrease in N concentration promoted lipid content production in both species: N. oculata content increased from 7.90 to 15.31% and C. vulgaris content increased from 5.90 to 16.41%.
Converti, Attilio, Allessandro Casazza, Erika Ortiz, Patrizia Perego, and Marco Del Borghi. 2009. Effect of temperature and nitrogen concentration on the growth and lipid content of Nannochloropsis oculata and Chlorella vulgaris for biodiesel production. Chemical Engineering and Processig. 48: 1146-1151.