The unicellular green alga, Haematococcus pluvialis, accumulates the highest level of astaxanthin among known
astaxanthin-producing organisms. Light is the most important factor to induce astaxanthin by H. pluvialis. Blue and
red LEDs, whose λmax’s are 470 and 665 nm, respectively, were used for internally illuminated light sources.
Fluorescent lamps were also used for both internal and external illumination sources. The astaxanthin levels in these
various lighting systems were analyzed and compared each other. The cultures under internally illuminated LEDs
accumulated 20% more astaxanthin than those under fluorescent lamp. Furthermore, LEDs generated much less
heat than the fluorescent lamps, which gives one more reason for the LEDs being a suitable internal light source for
astaxanthin induction. The results reported here would lead novel designs of photobioreactors with improvements
of illumination methods for high level of astaxanthin production. The maximum astaxanthin concentrations as well
as the astaxanthin yield per supplied photon were increased by at least 20% when blue or red LEDs were supplied.