Effects of Four Organic Carbon Sources on the Growth and Astaxanthin Accumulation of Haematococcus lacustris

The microalga <i>Haematococcus lacustris</i> has a complex life cycle and a slow growth rate, hampering its mass cultivation. Culture of microalgae with organic carbon sources can increase the growth rate. Few studies have evaluated the effects of organic carbon sources on <i>H</i>. <i>lacustris</i>. We compared the vegetative and inductive stages of <i>H</i>. <i>lacustris</i> under autotrophic and mixotrophic conditions using four organic carbon sources: sodium acetate, glycerol, sodium gluconate, and ribose, each at various concentrations (0.325, 0.65, 1.3, and 2.6 g/L). The cell density was increased by 1.3 g/L of glycerol in the vegetative stage. The rapid transition to the inductive stage under nitrogen-depletion conditions caused by 1.3 or 2.6 g/L sodium acetate promoted the accumulation of astaxanthin. The production of astaxanthin by <i>H</i>. <i>lacustris</i> in mass culture using organic carbon sources could increase profitability.