The optimization of the BG-11 culture medium nutrients using complex statistical design followed by incremental illumination was planned to stimulate the Haematococcus pluvialis growth and astaxanthin accumulation. Based on the Plackett-Burman design results, MgSO4·7H2O, H3BO3, and Na2CO3 were identified as critical components to improve the biomass and astaxanthin productivity. Using central composite design, their initial critical concentrations in the green stage were found as 57.5, 6.2 and 53.0 mg/L, while for the red stage, the 138.3, 8.5 and 41.0 mg/L, recorded as optimum respectively. Using the optimum media, growth and astaxanthin accumulation at the end of the phototrophic and photoinduction stages were boosted by 17 and 54% respectively. The results of scale-up coupled with incremental illumination in phototrophic stage revealed the biomass and astaxanthin concentration improved 50% and 60% over the BG-11 media under constant light intensity. Also, different optimum culture medium formula for green and red stages was proposed.
Keywords: Astaxanthin; H. pluvialis; Light-feeding strategy; Nutrients designing; Optimization.
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