2. Material and methods
2.1. Microalgae cultivation
Chlorella vulgaris (SAG 211-11 B) and Scenedesmus obliquus
(CCAP 276/3A) stock cultures were maintained in 2 L glass
photobioreactors aerated with 0.2 mm filtered air and mixed by
stirring. The medium was based on Wright's Cryptophyte
(WC) medium and contained 8.7 mg L1 K2HPO4, 85.0 mg L1
NaNO3, 36.8 mg L1 CaCl2.2H2O, 37.0 mg L1 MgSO4.7H2O,
12.6 mg L1 NaHCO3, trace metals and vitamins (Guillard and
Lorenzen, 1972). The pH of the culture was buffered at 8 by
addition of Tris buffer. The cultures were irradiated from one
side with daylight fluorescent tubes, giving a light intensity of
60 mE m2 s1 at the surface of the reactors.