## 3 Results
### First Stage
The determined cellular biomass yields ranged from 15.65 to 9.10 g\({}_{\rm d.m.}\)/L. The addition of aluminum at a concentration of 300 mg Al\({}^{3+}\)/L caused a significant reduction in the biomass yield (15.71 g\({}_{\rm d.m.}\)/L). Among the tested vitamins, supplementation with biotin and riboflavin in the entire concentration range did not cause any significant difference in the determined values of the biomass yield, which ranged from 19.52 to 23.23 g\({}_{\rm d.m.}\)/L. The addition of niacin at the doses of 700, 850, and 1000 ug/L caused a significant reduction in biomass yield, which ranged from 15.35 to 12.12 g\({}_{\rm d.m.}\)/L. The same phenomenon was observed with pantothenic acid at concentrations of 850 and 1000 ug/L, and the values of biomass yield were 16.55 and 14.68 g\({}_{\rm d.m. }\)/L, respectively. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type of Medium** & \begin{tabular}{c} **Concentration** \\ **[ug/L]** \\ \end{tabular}  & \(\mathbf{t_{lag}}\) **[h]** & \(\mathbf{t_{log}}\) **[h]** & \(\mathbf{\mu_{max}}\) **[h-1]** & **AOD** \\ \hline Control & 0 & 6.0 & 18.0 & 0.0341 \(\pm\) 0.0033 * & 1.542 \(\pm\) 0.204 a  \\  & 100 & 8.0 & 14.0 & 0.0323 \(\pm\) 0.0056 * & 1.116 \(\pm\) 0.143 b  \\  & 300 & 8.0 & 14.0 & 0.0339 \(\pm\) 0.0064 * & 1.113 \(\pm\) 0.071 b  \\ Biotin & 500 & 8.0 & 16.0 & 0.0335 \(\pm\) 0.0022 * & 1.202 \(\pm\) 0.038 b  \\  & 700 & 8.0 & 16.0 & 0.0301 \(\pm\) 0.0014 * & 1.179 \(\pm\) 0.072 b  \\  & 850 & 8.0 & 16.0 & 0.0279 \(\pm\) 0.0014 * & 1.098 \(\pm\) 0.097 b  \\  & 1000 & 10.0 & 16.0 & 0.0293 \(\pm\) 0.0020 * & 1.210 \(\pm\) 0.193 b  \\ \hline Riboflavin & 0 & 6.0 & 18.0 & 0.0341 \(\pm\) 0.0033 a  \\  & 100 & 6.0 & 18.0 & 0.0306 \(\pm\) 0.0021 b  & 1.173 \(\pm\) 0.178 b  \\  & 300 & 6.0 & 18.0 & 0.0289 \(\pm\) 0.0017 ab  \\  & 500 & 6.0 & 20.0 & 0.0291 \(\pm\) 0.0020 ab  & 1.129 \(\pm\) 0.137 b  \\  & 700 & 6.0 & 20.0 & 0.0283 \(\pm\) 0.0011 b  & 1.108 \(\pm\) 0.079 b  \\  & 850 & 6.0 & 20.0 & 0.0268 \(\pm\) 0.0010 b  & 1.140 \(\pm\) 0.040 b  \\  & 1000 & 8.0 & 20.0 & 0.0269 \(\pm\) 0.0022 b  & 1.153 \(\pm\) 0.053 b  \\ \hline Niacin & 0 & 6.0 & 18.0 & 0.0341 \(\pm\) 0.0033 a  & 1.542 \(\pm\) 0.204 a  \\  & 100 & 8.0 & 20.0 & 0.0210 \(\pm\) 0.0075 b  & 1.030 \(\pm\) 0.152 bc  \\  & 300 & 8.0 & 20.0 & 0.0221 \(\pm\) 0.0027 b  & 1.083 \(\pm\) 0.138 b  \\  & 500 & 8.0 & 20.0 & 0.0226 \(\pm\) 0.0022 b  & 1.163 \(\pm\) 0.126 b  \\  & 700 & 10.0 & 20.0 & 0.0214 \(\pm\) 0.0007 b  & 0.868 \(\pm\) 0.110 bc  \\  & 850 & 10.0 & 24.0 & 0.0169 \(\pm\) 0.0017 b  & 0.762 \(\pm\) 0.123 bc  \\  & 1000 & 12.0 & 26.0 & 0.0150 \(\pm\) 0.0020 b  & 0.694 \(\pm\) 0.069 c  \\ \hline  & 0 & 6.0 & 18.0 & 0.0341 \(\pm\) 0.0033 a  & 1.542 \(\pm\) 0.204 a  \\  & 100 & 8.0 & 20.0 & 0.0210 \(\pm\) 0.0075 b  & 1.030 \(\pm\) 0.152 bc [FONOTE:b]Footnote b: footnotemark: [ENDFOOTNOTE] \\ Niacin & 500 & 8.0 & 20.0 & 0.0221 \(\pm\) 0.0027 b  & 1.083 \(\pm\) 0.138 b  \\  & 700 & 10.0 & 20.0 & 0.0226 \(\pm\) 0.0022 b  & 1.163 \(\pm\) 0.126 b  \\  & 850 & 10.0 & 24.0 & 0.0169 \(\pm\) 0.0017 b  & 0.762 \(\pm\) 0.123 bc  \\  & 1000 & 12.0 & 26.0 & 0.0150 \(\pm\) 0  
The content of total carotenoids in the yeast cell biomass obtained after cultivation in the medium with potato wastewater and 3% glycerol was, on average, 73.06 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{g}\)\(\mathrm{d}\)\(\mathrm{m}\). (Table 3). A significant increase in the carotenoid content (146.73 \(\mathrm{\SIUnitSymbolMicro g}\)/\(\mathrm{g}\)\(\mathrm{d}\)\(\mathrm{m}\).) was noted only in the medium containing 300 mg Al\({}^{3+}\)/L. Supplementation of medium with barium, zinc, and manganese, as well as B vitamins, did not cause an increase in the overall carotenoid content in the cellular biomass. Based on the values of cellular biomass yield and the total content of carotenoids, the volumetric efficiency of biosynthesis (defined as the number of carotenoids obtained from 1 L of the culture medium) was determined.