STUDY OF CHEMICAL COMPOSITION AND PROPERTIES OF BIOMASS OF CHLORELLA SOROKINIANA UNDER INFLUENCE OF DIFFERENT PHYSICAL FACTORS

The paper presents data on the current issue of the processing of microalgae Chlorella sorokiniana, the richness of the vitamin and amino acid composition of which ensures its nutritional (twice as much as soy protein) and biological value. This article also provides information on the utilization of chlorella as an enrichment supplement to develop a modern Life Support System for manned spacecraft. Based on the data collected from various bibliographical studies, it is recommended to take into account the established positive effect of light exposure on the microalgae for the production of astaxanthin, as well as, to vary the composition of the nutrient medium in order to obtain a dry microalgae biomass with a fixed lipid, protein and starch content. The influence of various physical factors on the specificity of biochemical processes in the cell and the variation in the composition of dry biomass in the cultivation of Chlorella sorokiniana was studied. Experimental results of the application of a red laser (output power 1.6 mW, wavelength 0.63 mu m), the exposure to daylight (intensity 2800 Lux), infrared (power 250 W, intensity 14100 Lux) and ultraviolet (wavelength 280-315 nm) radiations of the microalgal samples are presented. The most significant concentrations of protein compounds (46.0% and 48.4% of dry biomass) were obtained after the exposure to daylight and to infrared radiation. In the last case, the fatty acid composition of the sample was represented mainly by unsaturated acids (77% by weight). The biomass of C. sorokiniana cultivated under the influence of daylight showed an increased content of chlorophylls a (19.3 mg/g), chlorophyll b (7.1 mg/g) and of total carotenoids (2.8 mg/g). Under the action of ultraviolet light, the quantity of saccharides increased (up to 430 mg/g). The data obtained enables to select optimal cultivation conditions of Chlorella sorokiniana in order to obtain a biomass with a given composition and properties.