# Evaluation of the Prospects for the Use of Microalgae in Functional Break Production
## 1 Introduction  
People have been using microalgae for food since ancient times [1]. The first documented data on the use of microalgae as food products date back to the XVI century. It is a historically documented fact that in 1521, biscuits made from dried spirulina layers were sold in Mexico City [1]. Microalgae can be used as industrial raw materials to produce allkinds of organic compounds (sorbitol, ethyl and methyl alcohols, acetone, organic acids, esters, etc.) [2; 3]. To date, the use of microalgae is a promising way to produce pigments such as chlorophylls, carotenes, etc. It can be especially noted that the pigments obtained in this way are not toxic. Chlorophyll obtained from microalgae is used in the cosmetic and food industries. In Japan, this pigment is used to color fish pastes, in Europe--oils and fats [4; 5]. Microalgae _Arthrospira platensis_, _Chlorella vulgaris_, _Dunaliella salina_ and others are common in the Baltic Sea. Cyanobacteria of the _Arthrospira_ genera is a promising biological raw material, because in addition to easily digestible proteins, lipids, and polysaccharides, it has a unique combination of biologically active substances (BAS): vitamins A, C, E, B groups, carotenoids, polyunsaturated fatty acids, chlorophyll, etc. [6]. Cyanobacteria are used in many areas of the biotechnological industry: the production of biofuels, animal and poultry feed, raw materials for pharmaceuticals, as well as biofertilizers [7]. Cyanobacteria have shown their high effectiveness for the treatment and prevention of human diseases. The possibility of using _Arthrospira_ microalgae for the biosynthesis of targeted secondary metabolites [8] is of particular interest. Spirulina was first discovered in the Baltic Sea by [PERSON] in 1993 [9]. _A. platensis_ of Baltic origin has a size of 3.0-5.0 um and forms tightly twisted spirals. They slide due to typical oscillatory, helical movements on the surface. Cyanobacteria form opaque structures, usually blue-green in color, but pinkish-red filaments have also been observed in the Baltic Sea [10]. Spirulina is very rich in various chemical elements and organic substances. Spirulina has soft cell walls that consist of mucopolysaccharides, so it is easily digested in the intestine [11]. Spirulina has a large (among organisms using photosynthesis) content (60-70% dry weight) of easily digestible (85-90%) protein [12]. So, its dry mass contains up to 77% protein and all 20 amino acids, but leucine, valine, and isoleucine are most common. Spirulina lipids are mostly polyunsaturated fatty acids. The proportion of linoleic and \(\gamma\)-linolenic acids reaches 1/3 of each of all fatty acids (13.1-31.5% and 12.9-29.4%, respectively) [13]. Carbohydrates are mainly represented in the form of rhamnose and starch, which are sources of \"fast\" energy that cells easily absorb. Cyanobacteria biomass can be used for weight-reducing programs due to its unique composition (high protein content and low lipid and carbohydrate content) [14]. Spirulina contains a large number of trace elements such as K, Ca, Mg and P; it also contains Mn, Cu, Mb, Co, Ni, Z, and B. In addition, spirulina can store a large amount of these trace elements in the biomass contained in the form of chelate complexes (Cu, Z, Cr, Mn) and Se-containing amino acids and proteins. Vitamins, such as B-group (B2, B3, B6) and vitamin E, are also found in spirulina [15]. _C. vulgaris_ are green eukaryotic microalgae of the _Chlorella_ genus. Chlorella, as well as spirulina, grows in water and prefers warm, stagnant reservoirs. In the Baltic Sea, chlorella grows in the southern part [16]. Chlorella includes about 650 compounds, such as vitamins, fats, essential amino acids, macro- and microelements in an easily digestible form [17]. Each cell of chlorella is a spherical or oval cell with a chloroplast and a nucleus, covered with a shell; the cell sizes are from 2 to 10 um.