Microalgae as a source of biologically active substances.

Recently, microalgae cultures have attracted more and more attention of researchers due to their ability to synthesize various biologically active substances, rapid growth of biomass and possibility of adjusting their biochemical composition. The total protein content in biomass depends on the type of microalgae and ranges from 30% to 70% of dry matter. The amino acid composition of the microalgae protein is very diverse and in terms of biological value is not inferior to the protein of animal origin. The amino acid characteristics of the artichoke include leucine, valine, isoleucine, phenylalanine, tyrosine, methionine, cysteine, and tyrosine. Microalgae can produce different types of lipids: triacylglycerols, phospholipids, glycolipids, or phytosterols. They contain fatty acids from C12 to C24, usually with C16 and C18 monounsaturated and polyunsaturated fatty acids. The lipid content of microalgae ranges from 20% to 50% of dry weight. Carbohydrates from microalgae are formed both in chloroplasts and in the cytosol, and their presence in the cell walls of intracellular microalgae and vacuoles provides cells with energy in the form of monosaccharides or polysaccharides. The most common monosaccharides are glucose, rhamnose, xylose, and mannose. Carotenoids in microalgae are usually present in low concentrations (0.5% µg⁻¹ of dry weight), although in some cases they can reach 10% µg⁻¹ when they are grown under unfavorable conditions (e.g. Dunaliella salina). The chlorophyll content of microalgae ranges from 0.5% to 1.0% of dry weight, mainly it is chlorophyll a, but some microalgae (e.g. Dinophyta) contain chlorophylls b and c as well. [ABSTRACT FROM AUTHOR]