title: Effect of light intensity and frequency of flashing light from blue light emitting diodes on astaxanthin production by Haematococcus pluvialis.
abstract: Flashing light from blue light emitting diodes is an effective method for the reduction of energy consumption in the bioproduction of astaxanthin by Haematococcus pluvialis. We investigated the effects of light intensity and frequency on the final astaxanthin concentration in bioproduction by H. pluvialis grown mixotrophically. The final astaxanthin concentration under illumination with flashing light, with frequencies ranging from 25 to 200 Hz, was dependent on the light intensity and on the duty cycle and was equivalent, or higher, in comparison with that under illumination with continuous light at the same incident intensity. The light intensity determined the maximum attainable concentration of astaxanthin under continuous illumination. Under illumination with flashing light, the ratio of the final astaxanthin concentration to the maximum concentration at a specific light intensity was correlated to the duty cycle in the frequency range from 25 to 200 Hz. The effect of lower frequencies on enhanced astaxanthin production under flashing light was also studied; at levels as low as 1 Hz, higher final astaxanthin concentrations were observed under flashing light compared to concentrations attained under continuous light.
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan. katsuda@kobe-u.ac.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Katsuda
authors.forename: Hironori
authors.initials: H
authors.lastname: Shiraishi
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishizu
authors.forename: Reza
authors.initials: R
authors.lastname: Ranjbar
authors.forename: Shigeo
authors.initials: S
authors.lastname: Katoh
mesh_terms: D000460:Chlorophyta / Q000378:metabolism / Q000528:radiation effects*; D008027:Light; D018462:Photobiology; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D024341:Xanthophylls; C005948:astaxanthine