Influence of inert gases on yeast in cavitation conditions

Abstract

The process of water disinfection with high content of Saccharomyces cerevisiae yeast type under cavitation conditions (frequency of 22 kHz) at saturation of the studied water with inert gases of different nature (argon, helium) was investigated in this work. The use of additional gas increases the bactericidal effect and facilitates the cavitation formation. The results of morphological features of yeast are presented, as well as images of cells based on the results of microscopic studies at the appropriate magnification, characteristic of a particular type of microorganisms. The values of the effective rate constants of yeast destruction are calculated. It is shown that the efficiency of water purification from yeast under gas/US conditions depends not only on the duration of the process, but also on the nature of the bubbled gas. The effective gas nature in the process of water purification from microorganisms is noted. A decrease of the number of bacterial cells was observed in the atmosphere of both investigated gases, but with different activity. Argon under cavitation conditions showed greater efficiency in the process of yeast destruction: kd(Ar/US) > kd(He/US). The dynamics of the yeast number under the influence of gas/cavitation is graphically presented. The degree of water disinfection > 99% was detected after the duration of the process for 1 hour in an argon atmosphere. NM = 100 CFU/сm3 under Ar/US reached after t=3600 s, and for Не/US only after t=5400 s. It was shown that the nature of gas under cavitation conditions affects the duration of the water purification process.