Effect of light and nitrogen concentration on the growth and lipid content of marine diatom, Chaetoceros calcitrans

The effects of light intensity (µ mol m-2 s-1) and different levels of Nitrogen was made on the biomass and lipid of microalgae Chaetoceros calcitrans under  laboratory conditions in the north of Iran in 2016. The pure strand of C. calcitrans with F/2 media (8 sets of 3 flasks) were placed in front of the light source at values of 80, 160, and 240 µ mol m-2 s-1. The cell count was collected in lasted 7 days. Every day cells were counted recorded. Maximum cell densities were approximately 279, 299, 395 and 402×106 cells ml−1in 25, 50, 75 and 100 % nutrient levels respectively, up to the 20th day of media enrichment, also maximum cell density was 98×106 cells ml−1 in 100% nutrient level and 240 µ mol m-2 s-1 up to the 20th day. Results showed that the lipid yield decreased significantly with increasing light levels. The total lipid was significantly higher (14.41%) in control compare with 25, 50, 75 and 100% nutrient levels. The total lipid at 80, 160, and 240 µ mol m-2 s-1 were 13.31, 12.09 and 10.17% respectively. The production and storage of lipids by microalgae in response to variations in environmental factors are specific for each microalgae species.