Astaxanthin production by Haematococcus pluvialis under illumination with LEDs

The photosynthetic microalga Haematococcus pluvialis, a potential source of astaxanthin, was cultivated under illumination with LEDs emitting red (λmax=625 nm), green (λmax=525 nm), blue (λmax=470 nm), blue-purple (λmax=410 nm) and purple (λmax=380 nm) light and a fluorescent lamp, and the effects of wavelength on cell growth and astaxanthin accumulation were studied. LEDs emitting light of short wavelengths (380–470 nm) were found to induce astaxanthin accumulation of up to 5–6% per dry cell, although the induction caused the suppression of cell growth. From these results, we proposed a new strategy of cultivating H. pluvialis under illumination with red LEDs without inducing a high level of astaxanthin accumulation, and then switching to illumination with blue LEDs at a high light intensity to induce a high level of astaxanthin accumulation.