Effect of inducing agents on growth and astaxanthin production in Haematococcus pluvialis: Organic and inorganic

•Astaxanthin biosynthesis by organic and inorganic inducing agents.•Acetate groups can be used as organic inducing substances to increase astaxanthin in Haematococcus.•High astaxanthin productivity accumulates under potassium acetate as an inducing agent.

Haematococcus pluvialis is a freshwater microalga with commercial importance owing to its ability to accumulate astaxanthin, a natural red pigment with beneficial biological activity belonging to the carotenoids group. The accumulation of astaxanthin from H. pluvialis UTEX 2505 was carried out by inducing agents. H. pluvialis UTEX 2505 was cultivated in an algal chamber with light intensity controlled at 104 µmol m−2 s−1 and light/dark cycles of 16:8 h. Continuous bubbles of air mixed with 2% carbon dioxide, at a flow rate of 0.67 vvm, were passed through a PTFE membrane filter at 25 °C. H. pluvialis UTEX 2505 was initially grown in NSIII medium for cell production until the exponential phase. Different concentrations of 10 - 100 mM sodium acetate, potassium acetate, magnesium acetate, and sodium hydrogen carbonate were then added, and the cells were induced to accumulate astaxanthin. Highest astaxanthin concentration and productivity were obtained with addition of 100 mM potassium acetate which can be added as an organic carbon source to mixotrophic cultivations as an inducing agent for astaxanthin accumulation by H. pluvialis.