Application of surfactants for controlling destructive fungus contamination in mass cultivation of Haematococcus pluvialis

Abstract

Large-scale cultivation of Haematococcus pluvialis is frequently contaminated by the destructive fungus Paraphysoderma sedebokerense, which can cause huge losses in astaxanthin production. Here, we propose the use of four commercial surfactants to control P. sedebokerense contamination in H. pluvialis cultures. In laboratory experiments, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate and primary alcohol ethoxylate treatments showed inhibitory effects on fungal contamination. Moreover, sodium dodecylbenzene sulfonate was the most promising because treatment at 7 mg L^-1 was effective against fungal infection without negatively affecting the growth or astaxanthin contents of H. pluvialis. This could be ascribed to their different cell coverings and structures. Additionally, applying sodium dodecylbenzene sulfonate to open raceway ponds prevented fungal contamination, and astaxanthin production reached 1.82 g m^-2. Therefore, sodium dodecylbenzene sulfonate can be used as an effective and economical control agent for commercial production of astaxanthin fromH. pluvialis.

Keywords: Astaxanthin; Haematococcus pluvialis; Open raceway pond; Paraphysoderma sedebokerense; Surfactant.