Spirulina Culture, production and applications

Global demand for protein is rising steadily as the world's population increases. The agri-food industry has responded to this growing demand with increased productivity based on intensification, fertilization and genetic modification. However, this demand cannot be met by simply increasing agricultural production without damaging the environment and depleting natural resources. Today's intensive agricultural systems have a detrimental effect on the environment due in particular to its increased emissions of greenhouse gases such as nitrous oxide (N ₂ O) linked to the use of nitrogen fertilizers, methane (CH ₄ ) from ruminant enteric fermentation, as well as carbon dioxide (CO ₂ ) emissions from the combustion of fossil fuels. A conversion of the food sector, or more accurately a transition to sustainable development, is therefore crucial to guaranteeing food supplies for 9.1 billion people by 2050, according to estimates by the United Nations Food and Agriculture Organization (FAO).

In 2020, protein-rich microalgae are being proposed as a sustainable alternative to animal protein sources. Thanks to its nutritional profile on the one hand, and its cultivation method, which requires no arable land and has a low environmental impact on the other, spirulina is a promising alternative to animal proteins. A traditional food for centuries in Africa, Latin America and Asia alike, spirulina has been attracting growing interest from the international scientific community since the 1970s, due to its potential use as a source of products with both nutritional and therapeutic virtues. Indeed, the therapeutic potential of this micro-algae appears to be significant, thanks to its main pigment, C-phycocyanin, which gives it its characteristic blue-green color. Some studies have, among other things, highlighted activities on the immune system, cancer, the fight against cell ageing, hepatoprotective and anti-inflammatory properties. Along with Odontella, Tetraselmis and Chlorella, spirulina is one of the 4 micro-algae currently authorized for human consumption, and accounts for 50% of the world's annual production of micro-algae. It is also widely cultivated in France, where there are 190 producers grouped together under the Fédération des Spiruliniers de France (2018 data).

The aim of this article is therefore to present an overview of the applications of spirulina, which appears to have vast potential. Historical aspects, cultivation, harvesting, extraction and valorization of molecules of interest are also discussed.

A glossary of terms is provided at the end of the article.