EFFECTS OF LIGHT INTENSITY, ILLUMINATION CYCLES ON MICROALGAE HAEMATOCOCCUS PLUVIALIS FOR PRODUCTION OF ASTAXANTHIN

Microalgae Haematococcus pluvialis was reported as one of the major producers of astaxanthin. Light stress was applied to enhance the astaxanthin content in H. pluvialis. H. pluvialis was cultivated in BG-11 medium for 12 days under irradiation of white plasma light, blue LED light and red LED light. Two-stage cultivation was applied by exposing H. pluvialis under low light intensity first, then further to nitrogen starvation and high light intensity for 3 days. The results of green stage indicated that white plasma with 24:0 light/dark (L/D) cycle was the best condition for cell growth with maximum cell density (8.58 ± 0.452 x 105 cells/ml) and specific growth rate (0.365 ± 0.004 day-1). After 3-day stress condition with high light intensity and nitrogen starvation, white plasma with 24: 0 L/D cycle was the best condition for lipid (0.055 ± 0.002 g/L) and astaxanthin production (0.049 ± 0.001 g/L). The lowest production cost for producing 1 g of lipid and astaxanthin was under red LED light with 24:0 L/D cycle.