Spirulina: Characteristics, Production and Applications

The blue green algae are the primitive members of the plant kingdom. The most of the blue-greens algae are unicellular, photoautotrophs and aerobic. They require mainly light, inorganic matter and oxygen for their growth. Spirulina are filamentous blue-green algae (cyanobacteria) always attracted the interest of researchers because they have simple cellular structure with a large surface area with respect to their body volume. This is a reason for getting large intakes of nutrients by Spirulina. They live in water bodied having access of water around it with high concentration of nutrients and CO2. They are very effective in the conversion of solar energy because of it they are good producer of biomass per unit area in the comparison of other terrestrial plants. Cyanobacteria have more than thirty thousand species which are used as unexploited resources and around 10 species are used in different commercial production.

Spirulina are very famous because it contains high value of protein and is very common cyanobacteria which can be easily grown in water and can be harvested commercially. Spirulina is commonly consumed as food by human in various countries, because it is a good source of vitamin, protein and aquaculture supplementary diets. These blue - green algae represent one of the mainly hopeful resources for many new products and purposes. Spirulina is especially protein rich because it contains 60-72 percent protein with respect to its dry weight. It also contains approx. 20 percent of phycocyanin, which is a blue pigment soluble in water and chlorophyll a, the green pigment. Cyanocobalamin which is called vitamin B12 is also present in good concentration in Spirulina.

Spirulina platensis is a cyanobacteria with multicellular filamentous structure, consisting of bluegreen filaments of cylindrical cells in unbranched helicoidal trichomes. Phosphorus and nitrogen present in agroindustrial as nutrients and known as effluents and also found in domestic wastewater becomes the cause of a serious problem eutrophication in any water body. But these nutrients are very important to increase the growth of plant as phytoplankton. They can be consumed as natural food for fish or for pharmaceutical purpose. Due to its high nutritional values Spirulina is one of the most hopeful microalgae for culture. β- carotene, provitamin A, vitamin C and E was also found in it. It is also a good source of fundamental fatty acid, GLA i. e. γ-linolenic acid maintained to have therapeutic characterstics. Some minerals as calcium, chromium, iron, magnesium, manganese copper, phosphorus, potassium, sodium and zinc etc are also found in it. Many research studies have been done related to the physiology of Spirulina in biotechnology, but the work related to genetic isn’t enough. Genetic work of cyanobacteria was generally known, though, there is a requirement for better strains for meticulous aims and methods gene transfer system for Spirulina. Spirulina is a bacterium which is oxygenic photosynthetic cyanobacteria and Prochlorales according to the classification in Bargey’s Manual of Determinative Bacteriology. In this classification sub-unit 16S is considered as a sequence of the rRNA. These microorganisms were classified into two genera in 1989, on the basis of the suggestion given by Gomont in 1892.

Now a day’s same classification is accepted. Currently, there are many disagreements about this classification of Spirulina. Botanists commonly identify this microorganism as amicroalgae because they are photosynthetic organisms. While, bacteriologists are comprise this microorganisms into bacteria on the basis of the main dissimilarity as a phospholipidic membrane between prokaryotes and eukaryotes.

The approach of industrial cultivation of algae is to be considered of national importance, as a unique source of bioactive phytonutrients, food additives, fodder, biofuel and other pharmaceutical components. In the last decades, several researches work have revealed that algae are a potential source of new bioactive compounds of pharmaceutical importance including antioxidants, natural pigments and food additives. The cyanobacterium Spirulina which is filamentous in structure appears to be an omnipresent component of the phytoplankton budding in seawater and ocean. Because of its attractive nutritional value, production and trade of Spirulina and its products have developed industrially. In China, total annual production capacity of Spirulina dry powder in 106 m2 total cultivation area is up to 400 t. At that time, Spirulina is used in food, feed, medicine and cosmetic industries. As a food, Spirulina is including high quality biologically active substances like vitamins, protein, minerals and many others. Its cell wall made up of polysaccharide which is easily digestible and easily absorbed by the human body. Tablets, drugs and capcules made from Spirulina are used as an additional food or nutritive food. In the formation of noodles, nutritious, stylish noodles, candies, beverages, cookies, coloring in chewing gums etc Spirulina is also used.

Spirulina is also used to support the growth of domestic animals, hen, prawn and foreign birds etc. Many protein rich foods like groundnut meal, fishmeal, and soybean meal, sprouts can be incompletely substituted by spirulina in the preparation of diets of cattle, fish, poultry and domestic animals. Adding to fodder in cattle and horse, the number of sperms in males and the fertility in females are improved. Disease resistance in chickens has been increased after feeding Spirulina because it increases the mononuclear phagocyte system function. When Spirulina is used in fowl diet then it provides yellowness and redness of broiler flesh.

Spirulina is also used for reducing the death rate and crop growing time and increase shell thickness, to promote the resistance and capability of prawns, to improve the survival rate, fish food for aquarium etc. Capsules of Spirulina have demonstrated efficient in poorer lipid level in blood, and in decreasing WBC after many treatments as radiotherapy and chemotherapy. It has also antiarthritic affect because of the anti-inflammatory and antioxidative properties of Cphycocyanin, anti-atherogenic property, tumor burden inhibition and cell degeneration.

New development in molecular biology permitted for improved perceptive of amazing microorganisms, the edible cyanobacteria from genus Arthrospira. Phylogenetic investigations and bioinformatics approach give information related to genomes structure and barrier in recombinant DNA technology. Genetic analyses recognized many genes responsible for hydrogen production, restriction-modification systems and stress adaptation, unraveling the processes sustaining the functions of the organisms. Genomics and proteomics research have proven the absence of toxicity factors, supporting the idea that Spirulina products are safe to eat. Research conducted for several years showed that Spirulina was extremely resistant to environmental stresses. Because of its benefits for human, animal and ecologic environment (photosynthesis), studies on cyanobacteria have been increased all over the world. Especially during the past half century, cyanobacteria has been used in photosynthesis and its genetic control, photoregulation of genetic expression, cell differentiation and N2 fixation, metabolism of nitrogen, carbon and hydrogen, resistance to environmental stress and molecular evolution. It is well recognized that the production of Spirulina is generally using CO2 as carbon source in the form of Na2CO3 and NaHCO3, bicarbonate which accounts to about 60 % of the nourish weight.

Spirulina is presently mass produced as a uniculture in outdoor as well as indoor cultivation systems; where in the growth medium utilized forms of it an important input and accounts for a main share of costs production.