Algae yield in a body of aqueous nutrient solution is increased by means of a nutrient thin-film surface culture substrate cycling between an illumination area and a non-illuminated refractory area in a closed system while feeding on the nutrient solution and CO.sub.2. Illumination includes both light...http://www.google.es/patents/US4324068?utm_source=gb-gplus-sharePatente US4324068 - Production of algae
