The biochemical composition of Cylindrotheca closterium (Ehrenb.) Rayman net Levin, as a source of biologically active substances in cumulative cultivation

In this work, we studied the biochemical characteristics of the diatom Cylindrotheca closterium in the cumulative mode of cultivation in different phases of growth. According to our data, in the exponential growth phase, C. closterium biomass is characterized by a minimum lipid content of 3% of dry biomass and a maximum carbohydrates content of 23% of dry weight. During the transition of C. closterium culture to the stationary growth phase, as in the case of a representative of diatoms, a rather high accumulation of total lipids is observed – to 28% dry weight, while the carbohydrates content decreases to 7%. At the end of the stationary phase (21st day of cultivation), the content of fatty acids is 50% of total lipids or 12.5% of dry weight. A certain relationship between the concentrations of fucoxanthin, total lipids and polyunsaturated fatty acids (PUFA) in the biomass of C. сlosterium diatom was recorded. During active growth in the exponential phase, the concentration of fucoxanthin was 0.5–1 mg∙g-1 dry weight. During the tranition of the culture to the stationary phase of growth, the concentration of fucoxanthin reached 7±0.2 mg∙g-1 dry biomass. At the end of the stationary phase, the concentration of fucoxanthin reached its maximum value of 20 mg∙g-1 dry weight.