Carbon penetrates into the diatoms both of carbon dioxide and of hydrocarbonate ions.However, all nutrient media for the diatoms  cultivation  still intendto use of CO2 from the atmosphere or balloon. The aim of the work was to evaluate the possibility of using sodium bicarbonate to provide carbon with C. closterium under intensive cultivation without supplying CO2 to the suspension. The culture was grown in the storage cultivation mode in a 1 L flask, on nutrient medium RS: 0.775, NaH2PO4 • 2H2O – 0.0641, Na2SiO3 • 9H20 – 0.386, Na2EDTA – 0.0872, FeSO4 • 7H2O –  0.045, CuSO4 • 5H2O –  0.2 • 10-3, ZnSO4 • 7H2O – 0.44 • 10-3, CoCl2 • 6H2O – 0.2 • 10-3, MnCl2 • 4H2O – 0.36 • 10-3, NaMoO4 • H2O - 0.12 • 10-3, –  in which 1.2 g were previously dissolved · L-1 sodium bicarbonate. The cell suspension was stirred using a magnetic stirrer (250 rpm). On the fourth day of the experiment, 1 g of NaHCO3 and 2 ml of 0.1 N hydrochloric acid were added to the culture to reduce the pH to 8.6 units. From the second day of the experiment, active growth was observed with a maximum productivity of 0.6 g · (l · day)-1 After adding 1 g · l-1 sodium bicarbonate to the actively growing culture and lowering the pH to 8.6 units. a decrease in the growth rate to almost zero was observed, but judging by the rate of increase in the pH of the medium during adaptation, the culture actively absorbed bicarbonate ions. The possibility of culturing benthic diatom C. colsterium on a nutrient medium with a high content of sodium bicarbonate was experimentally shown. It was found that on RS nutrient medium with the addition of 1.2 g According to our data, the optimal pH of the medium for the growth of C. сlosterium is in the range of 8.4–9.4 units. At higher values ​​(pH> 9.4), the growth of diatoms slows down, and when pH = 9.9 is reached, the culture goes into the dying phase


S. N. Zheleznova

junior researcher



R. G. Gevorgiz

senior researcher, PhD