Culture Medium and Growth Phase Modulate the Fatty Acid Composition of the Diatom Nitzschia palea (Kutzing) W. Smith-Potential Source for Live Feed and Biodiesel

The fresh water diatom Nitzschia palea was cultured in four different culture media viz., f/2, Walne’s, Chu and WC to determine the quality and production of lipids and fatty acids in this diatom during exponential and stationary phases of growth. The lipid content showed significant variation between culture media i.e. 10.97, 13.98, 25.43 and 21.43% in the exponential phase and 19.09, 21.41, 19.29 and 18.54% in the stationary phase in f/2, Walne’s, Chu and WC medium, respectively. The lipid fraction of N. palea was mainly composed of myristic acid (11.76 -19.8%), pentadecanoic acid (7.76 - 18.18%), palmitic acid (3.0 - 15.1%), palmitoleic acid (3 - 15.1%), arachidonic acid (5.03 - 21.61%) and eicosapentaenoic acid (2.61 - 19.86%). Saturated fatty acids (SFAs) production was found to increase from exponential to stationary phase in all the culture media studied. Monounsaturated fatty acids (MUFAs) were found to decrease in percentage from exponential to stationary phase in f/2 and Walne’s medium whereas in Chu and WC medium MUFAs showed an increase in percentage in the stationary phase. The polyunsaturated fatty acids (PUFAs) showed a decrease in quantity as the culture entered stationary phase. The results revealed that the culture medium and the growth phase affect the quantity of fatty acids considerably and the percentage of fatty acids in each medium and growth phase are significantly different (p<0.5). In N. palea appreciable amount of saturated and unsaturated fatty acids were found which establishes the importance of this diatom in the field of aquaculture as live feed and biofuel production.