A photobioreactor with pH control: demonstration by growth of the marine diatom Skeletonema costatum

A photobioreactor with pH control for cultivation of algae isdescribed. The magnetically stirred culture flask is connectedto separate reservoirs for medium and for acid and base (dilutedHCl and NaOH, respectively). A pH electrode is inserted intothe culture flask and coupled to a pH controller, which activatesacid and base titration at set points of pH 8.1 and 7.8, respectively.Illumination is provided by light tubes with a diel light :dark cycle. The use of the photobioreactor in batch mode isillustrated by showing pH curves in different growth phasesof the marine diatom Skeletonema costatum. The photobioreactorcan also be run as a semicontinuous or continuous reactor withslight modifications.