Microalgae or microscopic algae grow in either marine or freshwater systems. They are primary producers in the oceans that convert water and carbon dioxide to biomass and oxygen in the presence of sunlight.[2]
The oldest documented use of microalgae was 2000 years ago, when the Chinese used the cyanobacteriaNostoc as a food source during a famine.[3] Another type of microalgae, the cyanobacteria Arthrospira (Spirulina), was a common food source among populations in Chad and Aztecs in Mexico as far back as the 16th century.[4]
Today cultured microalgae is used as direct feed for humans and land-based farm animals, and as feed for cultured aquatic species such as molluscs and the early larval stages of fish and crustaceans.[5] It is a potential candidate for biofuel production.[6] Microalgae can grow 20 or 30 times faster than traditional food crops, and has no need to compete for arable land.[6][7] Since microalgal production is central to so many commercial applications, there is a need for production techniques which increase productivity and are economically profitable.