Abstract
Microalgae are drawing keen attention as alternative sources of sustainable energy or functional
materials. Photobioreactors are suitable for the production of high-value-added materials by microalgae
because those systems can minimize such uncertain factors as weather fluctuations that negatively affect
production. On the other hand, the utilization of artificial light sources in the photobioreactors increase
cost. Recently, light-emitting diodes (LEDs) and laser diodes (LDs) are expected to be effective light
sources for plant production in closed systems: “plant factories”. Even though LEDs and LDs can be
adopted for photobioreactors, relatively few studies have compared the effects of LED or LD irradiation
on the growth and productivity of microalgae with plants. This review summarizes the recent trials of
the utilization of LEDs or LDs for algal culture.
