Technical and physiological aspects of microalgae cultivation and productivity—spirulina as a promising and feasible choice

Abstract

Microalgae form a wide group of photosynthetic microorganisms, which include prokaryotic cyanobacteria (e.g., genus Arthrospira) as well as eukaryotic unicellular algae (e.g., genus Chlorella). Microalgae can be regarded as “microplants” able to convert carbon dioxide and water into organic compounds via photosynthesis. Nevertheless, compared with higher plants (agricultural crops), the microalgae have much higher areal productivities and high content of proteins, vitamins, antioxidants, minerals, and other health-promoting components. Moreover, they can be produced in nonarable areas. To reach high productivities of microalgal cultures, it is necessary to supply them with sufficient illumination, carbon dioxide, and minerals in culturing media. Nowadays, microalgae for human and/or animal nutrition are produced in different types of photobioreactors, where previously mentioned suitable conditions are ensured along with appropriate mixing. In order to decrease the cultivation cost of microalgae, it was proven that various flue gasses can provide carbon dioxide; sunlight is the costless illumination, and in some cases, suitable wastewaters can be used as the source of mineral nutrients. Considering the current state of knowledge, Arthrospira (spirulina, often rated among “superfoods”) seems to be the most promising microalga for widespread cultivation as for its cultivation and harvesting, no expensive technologies are needed.