(125d) Light Dynamics of Light Emitting Diodes (LED) in a Microalgae Culture

Light emitting diode (LED) can produce cost effective low wattage irradiance that is designed to be of the optimum spectral make up for growing specific microalgae species. That is, this artificial light source can conserve energy consumption by producing light only in the red (680nm to700nm) wavelength or the blue wavelength (420nm) for algae production. It can also be designed to produce wave lengths of light witch inhibit some nuisance microalgae species. The LED light sources can also be designed to pulsate which may reduce photoinhibition caused by continuous light sources at high irradiance levels and reduce energy consumption. Red light, however, attenuates over a shorter distance in the water column. This requires that an autotrophic photobioreactor be designed for a shallow culture. Optimization of photobioreactors supplied with low wattage LED light sources requires understanding of the light dynamics of these light sources in Microalgae culture. The purpose of this research was to study the light dynamics of red LED light in an algae culture. The light attenuation coefficient, optimum irradiance, maximum growth rate, and relationship between light attenuation and biomass concentration were examined and compared to prior research on other artificial light sources such as metal halide, high pressure sodium and Son Agro®.