PRODUCTION OF LIPID AND CARBOHYDRATE IN Tetradesmus obliquus UPSI-JRM02 UNDER NITROGEN STRESS CONDITION

Abstract

Nitrogen stress condition is believed to increase the production of lipid in microalgae, but the synthesis of both lipid and carbohydrate is less known. Therefore, the effect of nitrogen stress condition on the synthesis of lipid and carbohydrate of Tetradesmus obliquus UPSI-JRM02 was studied in a 2 L bioreactor system. The highest lipid and carbohydrate yields achieved under nitrogen stress condition were 37% and 23%, respectively. Nitrogen stress condition induced the accumulation of carbohydrate at early stage but started to reduce on day 4 when the carbon shifted towards lipid production. The fatty acid profile produced under nitrogen stress condition was composed of 54% polyunsaturated fatty acid (PUFA), 43% saturated fatty acid (SFA) and 3% monounsaturated fatty acid (MUFA). The biofuel properties of T. obliquus obtained under the nitrogen stress condition was within the range of biodiesel standard and is most suitable for the usage in cold country.