The aim of this work is to study the effect of non-thermal (low-temperature, cold) argon plasma on the inactivation of a traditional model organism – Saccharomyces cerevisiae. To generate non-thermal argon plasma, a source of nonequilibrium plasma based on a cold plasma jet of an electrodeless microwave discharge at atmospheric pressure was developed in the form of an experimental setup. A series of experiments were carried out to select the optimal parameters for yeast cell inactivation. The results of the study showed the antiyeast activity of non-thermal plasma for S. cerevisiae when acting on baker’s yeast cells seeded superficially on a dense nutrient medium (solid lawn). On the 1st day of incubation, a rounded zone of yeast growth inhibition was formed on the surface of the agar in the Petri dish, the diameter of which with an increase in the duration of plasma exposure to 20 min. was comparable to the diameter of the Petri dish. Also, on the first day of incubation in Petri dishes, the growth inhibition zone fluctuated in the range of 96…100 % of the total surface area of the Petri dishes after 10 and 20 min. of plasma exposure, respectively. In addition, a decrease in the colony size on the Petri dishes treated with a plasma jet was visually observed compared to the control (surface seeding not treated with a plasma jet). However, after 48 h of incubation, the growth inhibition zones in the Petri dishes after exposure to non-thermal plasma were overgrown, regardless of the duration of plasma exposure. After two days of incubation, statistically significant differences in the number of grown colonies of S. cerevisiae were observed compared to the control. The maximum exposure time (20 min.) led to a pronounced statistically significant decrease in the total number of CFU S. cerevisiae relative to the control by 86.6 %. After 10 min. exposure, a delay in the rate of yeast growth and a reliable decrease in the number of grown colonies of S. cerevisiae by 9 % relative to the control were observed.
