text: Light is what algae primarily need for growth as it is the most limiting factor. Many companies are investing for developing systems and technologies for providing artificial light. One of them is OriginOil that has developed a Helix BioReactorTM that features a rotating vertical shaft with low-energy lights arranged in a helix pattern. Water temperature also influences the metabolic and reproductive rates of algae. Although most algae grow at low rate when the water temperature gets lower, the biomass of algal communities can get large due to the absence of grazing organisms. The modest increases in water current velocity may also affect rates of algae growth since the rate of nutrient uptake and boundary layer diffusion increases with current velocity.
  Other than light and water, phosphorus, nitrogen, and certain micronutrients are also useful and essential in growing algae. Nitrogen and phosphorus are the two most significant nutrients required for algal productivity, but other nutrients such as carbon and silica are additionally required. Of the nutrients required, phosphorus is one of the most essential ones as it is used in numerous metabolic processes. The microalgae D. tertiolecta was analyzed to see which nutrient affects its growth the most. The concentrations of phosphorus (P), iron (Fe), cobalt (Co), zinc (Zn), manganese (Mn) and molybdenum (Mo), magnesium (Mg), calcium (Ca), silicon (Si) and sulfur (S) concentrations were measured daily using inductively coupled plasma (ICP) analysis. Among all these elements being measured, phosphorus resulted in the most dramatic decrease, with a reduction of 84% over the course of the culture. This result indicates that phosphorus, in the form of phosphate, is required in high amounts by all organisms for metabolism.
  There are two enrichment media that have been extensively used to grow most species of algae: Walne medium and the Guillard's F/ medium. These commercially available nutrient solutions may reduce time for preparing all the nutrients required to grow algae. However, due to their complexity in the process of generation and high cost, they are not used for large-scale culture operations. Therefore, enrichment media used for mass production of algae contain only the most important nutrients with agriculture-grade fertilizers rather than laboratory-grade fertilizers.