## 3 Results and Discussion
### The Thermal Analysis of Powdered Biomass of Rhodotorula glutinis var. rubescens
The thermal properties of _Saccharomyces cerevisiae_ and _Kluyveromyces fragilis_ biomass revealed temperature peaks of 66.66 and 63.67 \({}^{\circ}\)C, respectively, suggesting the denaturation of proteins [30]. The difference between the temperatures for _S. cerevisiae_ and _K. fragilis_ and this study strain was insignificant. The third peak indicating the presence of saccharides in powdered biomass samples was characterized by a similar shape and maximum temperatures of 161.93 \({}^{\circ}\)C after 168 h and 154.28 \({}^{\circ}\)C after 192 h, respectively, as shown in Figures 2-6. The shape of the fourth endothermic peak (Figure 7) was different from the previous figures. The course of this peak indicated the presence of a mixture of saccharides. The maximum temperature of the peak was 211.18 \({}^{\circ}\)C. The maximum temperature value of the peak was similar to the maximum temperatures of the peaks that indicated saccharide decomposition in yeast from earlier days of cultivation. The analysis of the thermal properties of _Tremella fuciformis_ polysaccharides illustrated a similar shape of the DSC curves [31], as shown in Figure 7. The fourth peak in Figure 8 is characterized by a different course and shape. The endothermic peak was characterized by a mild shape and course. The obtained maximum temperature was about 176.86 \({}^{\circ}\)C. The course and shape of the peaks indicated the presence of polysaccharides. DSC curves of _Saccharomyces cerevisiae_ cells had a similar shape when the temperature increased from 100 to 250 \({}^{\circ}\)C [32]. The Composition and Nutritional Suitability of Rhodotorula glutinis var. rubescens Yeast Biomass Lipid  
The cells with the highest lipid content as well as satisfactory biomass yield (41.55 g d.w./L) were selected for further analysis. Accordingly, biomass samples were obtained on the 5 th and 6 th day of cultivation. The high content of oleic acid (over 73% on average), followed by palmitic acid (>13%), stearic acid, and linoleic acid in approximate proportions characterized the lipids biosynthesized by _Rhodotorula_ cells (Table 1). C 18:0 and C 18:2 were dependent on the length of time of cultivation. The dominant share of oleic acid, and consequently the sum of MUFA content, influenced the general characteristics of _Rhodotorula_ lipids. Figure 8: The DSC curves of powdered biomass of _Rhodotorula glutinis_ var. _rubescens_ after 192 h cultivation in glucose fed-batch in potato wastewater. The composition of fatty acids is important for the prevention and treatment of diseases, which affects human health. It also determines the nutritional and technological suitability of fat. Based on fatty acids, many indices have been calculated to assess the usefulness of lipids from red yeast biomass in nutrition. The purpose of calculating the indicators (Table 2) was to assess the nutritional and/or pharmaceutical value of the lipids extracted from _Rhodotorula_ cells. The sum of PUFA to the sum of SFA is one of the indicators characterizing the nutritional and health value of fats. a well-known hypothesis is that all SFAs increase the levels of serum cholesterol [33]. Consequently, a higher ratio of PUFA/SFA might result in a more positive effect. This index for fat extracted from the biomass of red yeast was similar to some green (_Ulva reticulata_), red (_Gelidium micropertum_), or brown seaweeds (_Sargassum pallidum_) [34]. However, for some seaweeds (_Gracilaria changii_), this ratio can be higher than 2 or even 6 [35], as well as for sunflower oils (>4). On the other hand, the PUFA/SFA ratio indicator of lipids in red yeast is higher than that in cow milk [36], sheep milk [37], or lamb meat [38]. The \(\underline{\
abla}\)PUFA to \(\underline{\
abla}\)SFA index can be insufficient when n-3 PUFA and n-6 PUFA show a variety of effects on cardiovascular health. The consumption of fats rich in n-6 acids with a very high proportion of n-6 to n-3 acids is considered to contribute to