EFFECT OF Cr2(SO4)3 ON A STATUS OF CHLORELLA VULGARIS CULRURE CELLS UNDER THE DIFFERENT CONTENT OF NITROGEN SOURSE – KNO3 IN THE NUTRIENT MEDIUM

The Cr2(SO4)3 effect at 10–2–10–8 M concentration on the biomass yield, the concentration of intracellular protein, chlorophylls a and b, and carotenoids on the culture of Chlorella vulgaris strain C 111 IBCE C-19 was studied. In separate experiment series, the nitrogen source, KNO3 concentration was increased by 10 and 20%. Chromium (III) had an ambiguous effect on the functional and metabolic state of the chlorella culture, depending on its concentration and the nitrogen source – KNO3 concentration. In general, at 5.0 g/l KNO3 concentration, chromium sulfate in the 10–2–10–6 M concentration inhibited the algae culture development, and at the maximum concentration caused rapid death. In the initial period of cultivation, the level of chlorophylls a and b sharply increased, which, apparently, was of a compensatory-adaptive nature. From the side of biomass, the level of intracellular protein, chlorophylls, no dynamics of an oscillatory nature, inherent in the control variant of the nutrient medium, was revealed. An increase in the concentration of KNO3 to 5.5 g/l at Cr2(SO4)310–4–10–8 M concentration was not only accompanied by an increase in biomass, but also by a noticeable (17–74%) increase in the intracellular protein level, a decrease in the “tension” of the photosynthetic apparatus (judgment by the level of pigments) and restoration of the oscillatory dynamics of photosynthetic pigments. A further increase in the potassium nitrate concentration did not give a positive result and led to the aggravation of the chlorella culture functional and metabolic state.