Impact of blue light from LED on astaxanthin accumulation and transcription of key carotenogenetics in Haematococcus pluvialis

Haematococcus pluvialis can produce a high yield of astaxanthin under stresses, but this induced-biosynthesis is a relatively slow process and low productivity. As blue light can quickly promote astaxanthin accumulation in H. pluvialis, this study further investigated that the impact of blue light illumination from LED (3500 |xmol photons msec) on astaxanthin content, mRNA expression and regulation profiles of eight astaxanthin-synthesis-related carotenogentic genes in H. pluvialis. The results showed that (1) the astaxanthin content was enhanced to 3.03 mg/L in 18 days after blue light induction; (2) the expression levels of carotenoid genes ipi-1, ipi-2, psy, pds, lye, crtR-b, bkt2 and crtO were up-regulated in different time points during the cultivation; (3) the transcriptional expression of crfR-b, bkt2 and crtO was more efficient than other five genes under blue light induction. It was indicated that genes of crtR-b, bkt2 and crtO might be vital to astaxanthin production in blue light treatment for H. pluvialis. This study suggested that blue-light illumination in H. pluvialis is an effective stimulator to induce astaxanthin production in 11. pluvialis.