Effects of light-emitting diodes (LEDs) on the accumulation of lipid content using a two-phase culture process with three microalgae

•Three microalgae grew faster in blue LED than in white fluorescent light.•LED light intensities used: 100μmol/m2/s of blue, green, and red LED.•Blue and green LEDs influence microalgae growth and lipid production, respectively.•Two-phase culture was effective for biomass production and lipid accumulation. Conditions of light-emitting diode (LED) wavelength, light intensity, nitrate concentration, and time of exposure to green LED light stress in a two-phase culture were optimized for lipid production with three species of microalgae. Among the three microalgae, Nannochloropsis oculata showed the highest specific growth rate (μmax) of 0.037h−1 and the lowest saturation constant (Ks) of 1.32mg/L. The highest lipid contents of the three microalgae in the second phase under green LED light stress were 52.0% (w/w) for Nannochloropsis salina at 2days, 53.0% (w/w) for Nannochloropsis oceanica at 2days, and 56.0% for N. oculata at 2days. Fatty acid analysis of the microalgae showed that 85–87% (w/w) of total fatty acids from N. salina, N. oceanica, and N. oculata consisted of palmitic acid (C16:0) and oleic acid (C18:1).