The Spirulina is Earth's oldest living plant approximately 3.6 billion years ago and a first photosynthetic life form that has created our oxygen atmosphere so all life could evolve. Blue-green algae are the evolutionary bridge between green plants and bacteria. At present the main directions in microalgal biotechnology are biofuels, agricultural biostimulants for crop plants, wastewater treatment etc. Microalgal biotechnologies refer to the production of different products as phycocyanin, carotenoids, fatty acids and lipids for application in health food, cosmetics, food supplements, pharmaceuticals and fuel production. Spirulina has gathered enormous attention from research fraternity as well as industries as a flourishing source of nutraceuticals and pharmaceuticals. Microalgal groups of major importance are chlorophyte, bacillariophytes, while macroalgae are harvested from natural habitats. Algae that is currently cultivated for its maximum protein content is the cyanobacterium species Athrospira, which is commonly known as Spirulina.Spirulina is the most nutritious, concentrated food that is known to mankind containing antioxidants, phytonutrients, probiotics, and nutraceuticals. Spirulina is fast emerging as a complete answer to the varied demands due to its imposing nutrient composition which can be used for therapeutic uses. The United Nations world at food conference declared that Spirulina as the “best food for future”, and it is gaining popularity nowadays. World Health Organization has described spirulina as Mankind's best health product. According to UNESCO, spirulina is most ideal food for tomorrow. According to NASA and European Space Agency, it is one of the primary foods that can be cultivated in long-term space missions in space. FDA validated it as “One of the best protein source”. Intergovernmental institution permitted for the use of Micro-algae Spirulina against Malnutrition (IIMSAM).It has a considerable high content of micro and macronutrients. Its dry weight chemical composition includes 60–70% proteins, carbohydrates, vitamins like provitamin A, vitamin C, vitamin E, minerals such as iron, calcium, chromium, copper, magnesium, manganese, phosphorus, potassium, sodium and zinc. Essential fatty acids γ-linolenic acid (GLA), pigments like chlorophyll a, phycocyanin and carotenes are also present. Spirulina is also used in cosmetics, medicines and waste water treatment. Its cell wall consists of polysaccharides that have a digestibility of 86% and can be easily absorbed by the human body.