Ponomarova V. Preservation of Saccharomyces cerevisiae yeast immobilized in alginate gels after preservation at low temperatures

The object of the research is the influence of factors of low-temperature preservation and storage on viability, structural-functional state and biological properties of free and immobilized in alginate gel yeast S. cerevisiae. The purpose of the work is to investigate the influence of conservation conditions at low temperatures on the viability and structural and functional state of yeast Saccharomyces cerevisiae, immobilized in sodium alginate gel. Methods: microbiological; spectrophotometric; electron paramagnetic resonance; flow cytometry; confocal microscopy; cryobiological; cryomycroscopy; liquid chromatography; methods of statistical processing of results. Theoretical and practical results, scientific novelty: The viability of immobilized S. cerevisiae hyaluronium sodium alginate in the carriers of sodium alginate secretion depends on the cooling rate. Cooling at a rate of 1-5 deg / min to -40 °C and subsequent immersion of samples in liquid nitrogen can maintain the initial viability of immobilized yeast without additional protection by cryoprotectants. It has been established that the cryoprotective effect of solutions of sodium alginate is associated with the formation during the freezing of a highly viscous intercellular medium, which protects cells from damage by ice crystals and physical and chemical factors associated with crystalline formation. At the same time, the process of immobilization in alginate gel and further cooling of yeast cells initiates a moderate generation of AFC, the concentration of which exceeds the control value by 3 times. It promotes the increase of metabolic activity of yeast cells and activates the reparative processes in them. Thermoinduction of intracellular synthesis of trehalose by S. serevisiae cells before immobilization significantly increases their cryostatability and viability after cryopreservation using rapid uncontrolled freezing by direct immersion of samples in liquid nitrogen, which allowed developing a protocol for cryopreservation of immobilized yeast cells without the use of cryoprotectants and special cryogenic equipment. Protocols for cryopreservation of immobilized cells were developed for the first time S. cerevisiae using slow program cooling and uncontrolled cooling