Outdoor cultivation of Chlorella sorokiniana in third generation biorefinery: Resource savings through medium...

The reduction of resource requirements for the outdoor cultivation of Chlorella sorokiniana using 180 L flat panel photobioreactors through medium recycling was investigated in this study. Without medium recycling, algae grew in 13.6 d from 0.92 to 5.32 gL^-1with a productivity of 0.32 gL^-1d^-1. For the production of 748 g algae dry weight (DW), 152gkg^-1 N, 27 gkg^-1 P and 231 Lkg^-1 water were needed. A realistic cultivation model with the recycling of medium and a productivity of 0.4 gL^-1d^-1 was set up based on experimental data, in which the requirements decreased to 104gkg^-1 N, 24 gkg^-1 P and 141 Lkg^-1 water. Compared to the production of lutein-containing plant Tagetes erecta, water and potassium requirements of up to 91% less and 96% respectively and higher biomass productivity by the factor 3.7 was achieved.