Culture optimization and characterization of three Porphyridium strains for valuable compound production

The optimal conditions to maximize phycoerythrin- (PE) and exopolysaccharide (EPS)production in the three photoautotrophic red marine microalgal strains of Porphyridiumpurpureum (SAG 1380-la & -ld) and cruentum (UTEX 161) were researched. Design ofexperiment software (DoE) was used in planning and evaluation. Dependencies were foundbetween light intensity, nitrogen and magnesium concentrations, and the resulting PE andEPS productivities. The maximal PE productivity (4,96 μg mL-1d-1) was found in P.purpureum SAG 1380-ld. Contrasting, the highest EPS productivity (5,75 g L-1 d- 1) wasfound in P. purpureum SAG 1380-la. However, optimization efforts in EPS productionremained due to low dependencies under tested growth conditions. The optimal productinducing conditions for all strains were identified at ~40μmol photon m-2 s- 1and 9-15 mMnitrogen. The optimal magnesium concentration ranged between 5, 38 and 45 mM for UTEX161, SAG 1380-la and -ld, respectively. The pilot scale cultivation under greenhouseconditions could not be finished, because of temperature stress during the cultivation