Process Development for Astaxanthin Production by Microalgae

초록

In order to accomplish high-density cultivation of Haematococcus pluvialis UTEX 16, the present study has modified the Bold’s basal medium by optimizing the concentrations of Ca, Fe, Mg, Na, K, and trace elements in the medium. The culture conditions of temperature, pH, and light intensity have also been optimzed as 25oC, 7.5, and 40 mmol/m2/sec, respectively. Since this microalga shows low growth rate, easy contamination, and cell-settling, bubble-column type photobioreactor was selected for its mass cultivation. In this study, three different scale photobioreactors (400 mL, 2.0 L, and 10 L working vol.) were designed and constructed. And their operating methods have been developed including CO2 supplement (5 v/v %), nutrient feeding, and lumostatic operation. Under optimized conditions for cell growth and astaxanthin accumulation, the highest productivity of the process can be obtained as the final cell density of 1.6 ´ 106 cell/mL (20.5 g fresh weight/L) and astaxanthin concentration of 250 mg/L. At present, we are testing a two-stage system and scaling-up strategy.