Biotransformation of ethinylestradiol by microalgae.

The capability of biotransformation of 11 microalgae strains was tested on ethinylestradiol (EE). Seven strains were ineffective whilst Selenastrum capricornutum, Scenedesmus quadricauda, Scenedesmus vacuolatus and Ankistrodesmus braunii biotransformed the substrate. EE was converted by S. capricornutum in three products (ethinylestradiol glucoside, 3-beta-D-glucopyranosyl-2-hydroxyethinylestradiol, and 3-beta-D-glucopyranosyl-6beta-hydroxyethinyl estradiol) in 40%, 5%, and 5% yields, respectively. S. quadricauda transformed EE into 17alpha-ethinyl-1,4-estradien-10,17beta-diol-3-one (12%) and A. braunii transformed EE into 6-alpha-hydroxy-ethinylestradiol (25%). It is noteworthy that EE is converted in 92% yield in ethinylestradiol glucoside by S. capricornutum when using optimal algal density conditions.