Mokrosnop V. Effects of ethanol on Euglena gracilis cells under conditions of mixotrohpic cultivation.

The aim of the dissertation is to study the mixotrophic cultivation of microalga Euglena gracilis at the presence of ethanol in nutrient medium. Mixotrophic cultivation with using ethanol as substrate stimulates the growth rate of the culture in the exponential growth phase by 2,3 times and causing acidification of culture medium with time. Ethanol activates cell respiration, photosynthetic oxygen evolution and increases reduction potential of the cells in lag phase of the culture growth. Adding sodium glutamate with ethanol simultaneously to the nutrient medium strengthens the noted effects of ethanol. Biochemical composition of the cells of mixotrophic cultures E. gracilis changing over cultivation time. Content of photosynthetic pigments, chlorophylls and carotenoids, decreases at the first days of cultivation, while paramylon concentration has sharp increases. Maximum accumulation of photosynthetic pigments which indicate about increase photosynthetic capacity of the cells is observed in transient and stationary growth phases of mixotrophic cultures. The highest content of fat-soluble antioxidants, ?-carotene and tocopherols, was in volume unit of the culture with ethanol and sodium glutamate in stationary growth phase. Received evidence suggest about effective metabolism of ethanol by the cells of E. gracilis, that cultivating under light conditions.