Abstract
The continuing growth of the world's population, combined with climate change, poses a growing challenge to ensuring food security in the 21st century. Animal protein, e.g., from beef, is a particularly rich source of protein, but there is by no means enough arable land on earth to transfer the animal meat-rich nutritional style of the early industrialized countries to the global South. A hitherto largely neglected option for the production of proteins is the cultivation of microalgae and cyanobacteria, which already have a long history of use as a human or animal food for their nutritional and environmental merits. In particular, Limnospira platensis (Spirulina and formerly Arthrospira platensis)-a filamentous cyanobacterium-is considered the "food of the future" since it is a viable source of vegan protein. In this manuscript, we review the scientific literature as well as national and intergovernmental agency statements regarding the quality and quantity of AP-based proteins. The content of AP protein is discussed in relation to other species and different cultivation conditions, as well as to traditional crops and animal husbandry. The amino acid profile and quality assessment of AP as a dietary protein are discussed. In addition, the environmental aspects of AP production are considered, and the role of AP in efforts to bridge the 'protein gap' to improve nutrition and food security is discussed.