In contrast to Chlorella vulgaris, Spirulina platensis is a multicellular microalgae that usually consists of three to four cells. It is rich in proteins (amino acids), iron, vitamins and, in addition to essential amino acids, also contains numerous vital minerals such as calcium, phosphorus, magnesium and various trace elements. In addition, this microalgae contains the secondary plant substance phycocyanin, which is responsible for its blue color and strengthens the activity of the lymphocytes and the immune system. Spirulina soothes gastric mucosal inflammation and helps lower cholesterol levels. For sale, the dried biomass is usually pressed into tablets, enclosed in capsules or pulverized.
Spirulina grows mainly in salt water. It inhabits shallow, subtropical to tropical waters with a high salinity, especially in Central America, Southeast Asia, Africa and Australia. Spirulina has always been used as food by the people living in these waters, for example by the Kanembu on Lake Chad in Africa and on Lake Texcoco in Mexico.
Spirulina algae are grown in open and closed aquacultures at a water temperature of up to 37 degrees Celsius. The optimal growth of spirulina depends largely on the amount of carbon dioxide (CO2) made available. Therefore, in addition to the carbon dioxide that enters the culture from the air, aquacultures are also supplied with CO2 from various sources. In this way, the spirulina not only grows faster, but also produces significantly more oxygen. For harvesting, the culture is pumped through a filter or a continuous centrifuge, then the biomass obtained in this way is dried with hot air or in sunlight. Since microalgae have neither roots nor leaves, they use all the energy from the sun to produce bioactive nutrients.