Effects of nitrogen source on enhancing growth conditions of green algae to produce higher lipid

Abstract

Microalgae represent a potential source of biological material to produce biodiesel. This study focused on the effects of nitrogen concentration to enhance lipid content from Chlorella sorokiniana and their potential use to serve as a raw material for biofuel production. Light intensity and different nitrogen concentrations were used to determine the optimum cultivation environment for the fresh water microalgae, C. sorokiniana. The effects of various nitrogen sources were examined in order to determine the optimum lipid content produced by the microalgae. It was found that the optimum cultivation of microalgae growth has caused the biomass growth and has led to higher lipid production. The growth rate and lipid content were determined by measuring the optical density at 620nm and fluorescence intensity using Nile red method. Microalgae of 10% (v/v) concentration was found to be the optimum inoculum concentration with higher growth rate obtained when compared to 50% (v/v). The NH4NO3 nitrogen concentration showed greater lipid production compared to NaNO3 cells cultivated with final lipid content. The 0.2M of NH4NO3 nitrogen concentration produced highest lipid (3.138 a.u), when compared to two different nitrogen sources: NH4NO3 and NaNO3 with different concentrations.