The aim of the study was to investigate the impact of light and dark (L/D) period on the biosynthesis of astaxanthin in green alga Haematococcus pluvialis. The astaxanthin was extracted from H. pluvialis with DMSO and the astaxanthin content was determined by the UV-Spectrophotometer. H. pluvialis was incubated under 10:14 h (L/D) period exposed to sunlight at 32±2oC temperature, the astaxanthin biosynthesis was compared with the culture which was incubated in controlled air-conditioned culture room of 16:8 h (L/D) period at 25±2oC. Highest astaxanthin content was found as 0.045 µg mL- 1 in H. pluvialis culture which was exposed to sunlight under 10:14 h (L/D) on 9th d of study. Under 16:8 h (L/D) period at 25 ± 2oC, the highest astaxanthin content was found as 0.04 µg mL-1 on 17th d of study. From our present investigation, it is apparent that the 10:14 h (L/D) period is more effective in promoting astaxanthin content in green alga Haematococcus pluvialis.
Haematococcus pluvialis, Astaxanthin, Biosynthesis