Supplementation with polyalcohols and sequential mixotrophy dilution photoinduction strategy boost the accumulation of astaxanthin by Haematococcus pluvialis

Two-stage strategy and sequential mixotrophy dilution photoinduction (SMDP) as a novel culture strategy were evaluated by Haematococcus pluvialis. Also, the feasibility of using polyalcohols in comparison to monosaccharides, oligosaccharides and sodium acetate to promote cell growth of H. pluvialis was investigated. The addition of polyalcohols boosted cell mass by 1.6 folds compared to the sodium acetate. In SMDP strategy after mixotrophic stage, cells were diluted to reduce the nitrate concentration and then exposed to moderate light intensity to bolster the survival rate of the cells in comparison to two-stage strategy. The survival rate after the overnight was 1.29 folds over the two-stage strategy. When the cells were exposed to photoinduction phase in SMDP strategy, astaxanthin concentration was reached by 1.42 folds over the two-stage strategy. Also, the addition of glycerol was positively correlated with the accumulation of astaxanthin, which was on average 1.56 folds greater than what was achieved by culture provided with sodium acetate. Accordingly, the polyalcohols such as glycerol as a carbon source and SMDP as a cost-effective and time-saving cultivation strategy induced a better growth performance of H. pluvialis and a higher astaxanthin concentration.