Optimization of culturing conditions of Porphyridium cruentum using uniform design.

摘要

The red microalga Porphyridium contains many valuable compounds such as polysaccharides, PUFA and phycoerythrin (PE). A uniform design method and regression analysis were used to investigate effects of initial pH, light intensity, inoculation ratio and liquid culture vol. on optimal biomass, exopolysaccharides (EPS) and PE production by Porphyridium cruentum in batch culture on a laboratory scale. Using regression analysis, models were obtained to clarify the effects of individual factors and their interactions on biomass, EPS and PE production by P. cruentum. Optimal culture conditions were: for biomass production - pH 5.0, light intensity 7098.0 lux, inoculation ratio 1:17.2, and liquid vol. 100.0 ml; for EPS production - pH 5.0, light intensity 4501.0 lux, inoculation ratio 1:20, and liquid vol. 100.3 ml; and for PE production - pH 8.0, light intensity 7100.0 lux, inoculation ratio 1:20, and liquid vol. 100.3 ml. Predicted max. biomass yield of 3.27 g/l, EPS yield of 543.1 mg/l and PE yield of 132.0 mg/l were confirmed from experiments performed under optimum culture conditions in a reciprocal shaker. The statistical methods used are suggested to be useful strategies for optimizing culture conditions for other microalgae.