Use of RGB LEDs and Fluorescents Lamps as Light Sources to Grow Microalgae in a Photo-Bio Reactor (PBR)

Abstract

Biomass production from high oil content microalgae is considered as a source for biofuel production. High oil content microalgae can be produced in open ponds or closed photobioreactors (PBR). In order to grow high oil content microalgae efficiently, parameters such as illumination for photosynthesis, medium pH, CO2 consumption, and medium nutrient content must be monitored and controlled precisely. The control of illumination is the most critical parameter because illumination is the most expensive parameter of algae production in a closed PBR operating 24 hrs a day. In this research, all parameters except illumination source and intensity were kept the same for the growth of Chlorella kessleri (UTEX 398) microalgae. In the experiments red LED, blue LED and fluorescent lights were used separately as the illumination sources. The results, after a period of seven days of growth, showed the effect of the three illumination sources relative to cell count, cell weight, and cell size. The data collected was used to determine which light source and intensity was the most energy efficient for algae production. The results showed that red LED light was more efficient in the most cells at the highest weight while blue LED light was more efficient in producing larger cell sizes than the other light sources.