Phototrophic algae need (sun-)light, water, carbon-dioxide and nutrients for growing. In nature light is provided by the sun, whereas in algae cultivation systems the light could also be provided arteficially through LEDs or fluorescence lights. The light is used as energy source for photosynthesis processes, for which also carbon-dioxide must be provided (into the water). The carbon dioxide may be provided from nearby industries, where it is generated as waste gass.
Photobioreactors aim to present the optimum life conditions for algae to reach optimum growth rates. For this, it is important to mind the temperature of the water and to ensure a good light supply. To obtain optimum growth rates and cost-efficient productions these components must be well balanced.