Optimization of growth and EPS production in two Porphyridum strains

Due to the relatively low yield of exopolysaccharides from microalgae compared to other microorganisms, their production is more challenging and needs to be optimized. Porphyridium sordidum and Porphyridium purpureum growth and exopolysaccharide production were optimized by testing influence of light at different wavelengths and varying nutrients as well as abiotic factors. White light was identified as the most suitable for both strains concerning growth and exopolysaccharide production. CaCl2 was identified to have the greatest influence on growth and exopolysaccharide production for P. sordidum; NaCl and KH2PO4 revealed to be most beneficial for P. purpureum. The cultivation medium was optimized to enhance biomass production using the Taguchi design. Additionally, the most prominent abiotic factors for exopolysaccharide induction were determined. Finally, the results were combined in an optimized two-stage cultivation and increased EPS production by 3.4 times for P. sordidum and by 1.2 times for P. purpureum compared to the initial conditions.