The effect of nutrient arrangement on biomass growth and lipid content of microalgae Nannochloropsis oculata in internally illuminated bubble column photobioreactor

Microalgae is one of favorable biofuel raw material which has wide potential. The application of microalgae as an alternative energy raw material is based on its ability that can be reproduced continously. Hazards from fossil fuel combustion on the environment are also a consideration that favored the use of biofuels. Nannochloropsis sp. is a type of microalgae that produce lipid as its main product. However, the utilization of microalgae in Indonesia has not been executed due to some drawbacks, one of them is the low biomass yield produced by photobioreactors when used on an industrial scale. Nutritional intake is one of the factors that influence the growth rate of microalgae biomass. This research contains the comparison of growth rate and lipid content of Nannochloropsis oculata that was cultivated in a pilot scale bubble column photobioreactor with internal illumination with three different Walne composition medium, which are phosphate addition, nitrate reduction, and control. The objective is to determine optimum phosphate and nitrate composition in the Walne medium for growth rate and lipid content of Nannochloropsis oculata. On this research, medium with phosphate addition produces the highest biomass, which is 0,048 g/L.t he highest lipid content was found in medium with nitrate reduction which contains 25,77% of lipid out of its biomass.