Effects of using light-emitting diodes on the cultivation of Spirulina platensis

Various light-emitting diodes (LEDs) with different light wavelengths and illumination intensities were employed to explore the effects of light source on photoautotrophic cultivation of Spirulina platensis. From the experimental results, red LED exhibited the highest specific growth rate of 0.40 (day−1) under the condition of 3000 μmol m−2 s−1. Blue LED showed the least efficiency in the conversion of photon to biomass. Hence, a modified Monod model was proposed to fit the specific growth rates of S. platensis from different light sources. The light intensity threshold for minimum photoautotrophic growth was also determined. In comparing the economic efficiency of energy to biomass, the use of red LED gave the most effective performance for the photoautotrophic cultivation.