AbstractThe optimisation of lipid and carbohydrate yields and productivity is important for enhancing microalgae biofuel production. This study aims to optimise the growth conditions of Tetradesmus obliquus UPSI-JRM02 for high lipid and carbohydrate production and to examine the synthesis of these biomolecules under nitrogen stress conditions. The optimisation study was carried out using response surface methodology with Design Expert software. Four variables (nitrogen concentration, temperature, pH, and light intensity) were optimised to enhance T. obliquus productivity. T. obliquus was then cultured in optimised conditions before being introduced in nitrogen stress condition to further increases the production of lipid and carbohydrate yields. The results indicated that the highest lipid (33 mg/L/day), carbohydrate (51 mg/L/day) and biomass (115 mg/L/day) productivity were produced at a nitrogen concentration of 400 mg/L NO3-at 36 oC with pH of 9.8, and light intensity of 23,500 lux. The lip.....