Життєздатність спорогенних бактерій в атмосфері інертних газів

Abstract

The viability of sporogenic bacteria under the conditions of bubbling inert gases (argon and helium) through the water system was investigated and the action of each studied gases on the process of its destruction in water was compared. Bacillus cereus bacteria type were as the investigated microobjects and, as the predominant microflora of different natural waters, with an initial microbial load of 104 per 1 cm3 of investigated water. According with the first-order kinetic equation were calculated the values of the effective rate constants of the bacteria destruction. The effective gas nature in the process of water purification from microorganisms is noted. The experiments were carried out in a glass reactor with constant cooling of tap water. The growth of the investigated bacteria were carried out by the deep method, followed by storage in a thermostat at T = 30 °C for 48 h. The number of microorganisms per unit volume of investigated water was determined by the total number of bacteria grown on the culture medium on Petri dishes and expressed in colony-forming units. The total flow rate of the bubbled gas was 1.4 dm3, which was fed at a rate of 0.2 cm3/s to the investigated water volume (75 cm3) throughout the duration of the process. The calculated total microbial count in natural water and various industrial wastewater was used to determine the initial number of microorganisms per unit volume of investigated water. The dynamics of bacterial numbers under the influence of gases on the water system is presented graphically. Colonies of B. cereus bacteria type are presented during growth on nutrient medium before and after bubbling of microbial water with gas. Decreasing of the bacterial cells number was observed in the atmosphere of both investigated gases, but with different activity. Comparison of the values of the effective rate constants of bacteria for argon and helium showed that the cell number decreased more actively under argon bubbling conditions. Active destruction of microorganisms under argon bubbling compared to helium was observed, regardless of the initial bacterial count in 1 cm3 of investigated water. The effect of argon on water containing bacteria is described by the greater value of the effective rate constant of cell destruction: kd(Ar) > kd(He). It is shown that the efficiency of water purification from microorganisms depends on the nature of the bubbled gas.