## 2 Results
### Evaluation of Yarrowia lipolytica Yeast Cell Growth in Plasma Water-Based Media  
This study confirms the effect of plasma water on the growth of _Yarrowia lipolytica_ yeast cells, using the optical density (OD\({}_{600}\)) of the media and the yield of yeast cell dry matter as measures. Figure 1 illustrates the changes in the OD\({}_{600}\) parameter over an 8-day culture period.  
The OD\({}_{600}\) values curves for the conducted cultures exhibit a similar course, peaking between 96 and 120 h of culture. The highest OD\({}_{600}\) values were observed for yeast cultured in Nantes plasma water-based media (commercial water from Boleslawiec). At day 5 (120 h), the OD\({}_{600}\) parameter reached approximately 42.1 \(\pm\) 1.5. Slightly lower optical density values were observed for the culture that was based on plasma water in contact with nitrogen (PWTN) with a maximum of 34.5 \(\pm\) 1.2 at a cultivation time of 96 h. The culture grown on plasma water in contact with air (PWTA) exhibited a considerably lower optical density of the medium, not exceeding the value OD\({}_{600}\) = 25. Compared to the microbiological media used, which varied regarding the type of water employed, the control medium (prepared on distilled water) exhibited markedly lower optical density. The maximum value at 96 h was only 17.6 \(\pm\) 1.8, which was twice as low as that in the Nantes water medium, showing the highest values.  
Additionally, the yeast cell dry mass was measured. Figure 2 illustrates the fluctuating yield of _Yarrowia_ yeast cell dry matter over an 8-day culture.  
The dry cell mass yield curves of yeast grown in plasma water-based media align with the optical density data exhibited in Figure 1. The best yeast growth parameters and highest biomass yield over the culture cycle were found when utilizing Nantes water with enhanced singlet oxygen content. On day 5 of the culture, the maximum biomass synthesis was 16.31 \(\pm\) 0.91 g/L, which is approximately 9.5 g/L greater than the control culture. Cultures based on plasma water in contact with air or nitrogen resulted in higher biomass yields of approximately 2-4 g/L. It is worth noting that the use of plasma water in the media (regardless of the plasma treatment) increased the logarithmic growth phase of the  
Figure 1: Growth curves of yeast _Yarrowia lipolytica_ growing in the medium based on Nantes plasma water with heightened singlet oxygen level or on the water treated with low-temperature, low-pressure glow plasma in contact with air (PWTA) or nitrogen (PWTN).  
Figure 2: Dry cell mass of yeast _Y. lipolytica_ cultivated in the medium based on Nantes plasma water with heightened singlet oxygen level or on the water treated with low-temperature, low-pressure glow plasma in contact with air (PWTA) or nitrogen (PWTN).  
microorganisms, as shown in Figures 1 and 2. In the standard medium, the yeast reaches the stationary phase after roughly 55 h. In contrast, when using media containing plasma water in touch with nitrogen or air, the logarithmic growth phase continues for up to about 72-96 h, and it is even longer in the case of water containing an elevated amount of singlet oxygen.  
To evaluate the effect of plasma treatment of the water utilized in microbiological media, specific kinetic parameters for distinct cultures were evaluated and are displayed in Table 1.  
A comparison was conducted to assess the specific growth rate of the microorganisms, maximum biomass concentration and substrate biomass yield. Nantes plasma water yielded the highest values for all parameters. This culture's maximum specific growth rate was roughly 1.6-2.2 times higher than PWTA and PWTN media, respectively, and approximately 2.4 times higher than the control medium. The maximum biomass concentration expressed as the number of colonies count was 0.55-0.88 higher in comparison to the media with plasma water under air or nitrogen or the control medium.