## 3 Results
### Trials in Treated Second Cheese Whey  
The five microorganisms that presented biomass production on lactose-based media, namely _C. curvatus_ ATCC 20509, _C. curvatus_ NRRL \(\Upsilon\)-1511, _D. hansenii_ ACA-DC 5079, _P. laurentii_ NRRL Y-2536, and _P. laurentii_ NRRL YB-3594 were batch-cultivated in shake flasks in treated second CW, and the results are presented in Table 4. _C. curvatus_ ATCC 20509 fully assimilated lactose, partially consumed FAN (31.6 mg/L), and protein (0.29 g/L), producing 22.4 g/L TDW and 3.4 g/L intracellular lipids (14.7% \(w/w\) of lipids in TDW). _C. curvatus_ NRRL Y-1511 also assimilated lactose, partially assimilated FAN (36 mg/L), and protein (0.47 g/L), producing 20.6 g/L TDW and 3.2 g/L intracellular lipids (K\({}_{\text{L/X}}\) = 0.16 g/g). _P. laurentii_ NRRL Y-2536 fully consumed lactose, whereas free amino nitrogen (32.1 mg/L) and protein (0.13 g/L) were partially consumed, producing  
Figure 1: Kinetics of _Cryptococcus curvatus_ ATCC 20509 batch cultivation in semi-defined medium, with lactose as carbon source (S\({}_{0}\approx\) 118 g/L) and an initial C/N ratio \(\approx\) 124 moles/moles. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \begin{tabular}{c} **C/N** \\ **Moles/Moles** \\ \end{tabular} & \begin{tabular}{c} **S\({}_{0}\)** \\ **(g/L)** \\ \end{tabular} & \begin{tabular}{c} **Time** \\ **(h)** \\ \end{tabular} & \begin{tabular}{c} **S\({}_{\text{cons}}\)** \\ **(g/L)** \\ \end{tabular} & \begin{tabular}{c} **X** \\ **(g/L)** \\ \end{tabular} & \begin{tabular}{c} **L** \\ **(g/g)** \\ \end{tabular} & \begin{tabular}{c} **Y\({}_{\text{NS}}\)** \\ **(g/g)** \\ \end{tabular} & \
\begin{tabular}{c} **K\({}_{\text{L/X}}\)** \\ **(g/L)** \\ \end{tabular} &
\begin{tabular}{c} **P\({}_{\text{L}}\)** \\ **(g/g)** \\ \end{tabular} \\ \hline
14 & 46.3 & 139 & 46.3 \(\pm\) 2.0 & 20.0 \(\pm\) 1.9 & 1.5 \(\pm\) 0.2 & 0.43 & 0.03 & 0.08 & 0.011 \\ \hline
124 & 58.3 & 96 & 58.0 \(\pm\) 2.7 & 22.4 \(\pm\) 2.2 & 7.3 \(\pm\) 1.2 & 0.37 & 0.13 & 0.33 & 0.080 \\ \hline
124 & 118.4 & 144 & 118.0 \(\pm\) 3.6 & 44.0 \(\pm\) 2.9 & 15.8 \(\pm\) 1.6 & 0.38 & 0.13 & 0.36 & 0.110 \\ \hline
337 & 107.0 & 111 & 36.0 \(\pm\) 1.8 & 10.2 \(\pm\) 1.8 & 4.2 \(\pm\) 0.9 & 0.28 & 0.12 & 0.41 & 0.038 \\ \hline
482 & 152.8 & 160 & 33.0 \(\pm\) 2.1 & 14.9 \(\pm\) 2.1 & 8.7 \(\pm\) 1.6 & 0.45 & 0.26 & 0.58 & 0.054 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Quantitative data originated from kinetics of C. curvatus ATCC 20509, cultivated on a semi-defined medium, with lactose as a carbon source, and various initial lactose (S0) concentrations and C/N molar ratio media. Culture conditions as in Section 2; standard error for most experimental points was \(\leq\)17%. 22.0 g/L TDW and 1.2 g/L intracellular lipids (6% \(w/w\) in TDW). As in the previous set of experiments (screening on lactose-based media) this strain also produced significant quantities of EPS, therefore, dry weight determination included both the produced EPS and the yeast dry cells. Due to the presence of polysaccharides, the texture of biomass was gummy, and the fermentation broth was thick with high viscosity. It was only possible to follow the kinetics of lactose, and one final measurement of biomass was performed after complete lactose consumption (at t = 119 h after inoculation). For _P. laurentiti_ NRRL YB-3594 culture, lactose was consumed (55.7 g/L), whereas free amino nitrogen (33.3 mg/L) and protein (0.09 g/L) were partially consumed, producing 14.7 g/L dry biomass and 1.0 g/L intracellular lipids (6.9% w/w in TDW) in 101 h of batch cultivation. Finally, concerning the cultivation of strain _D. hansenii_ ACA-DC 5079, it consumed only an amount of the available lactose (c. 31% \(w/w\), viz. 18.1 g/L), producing 8.3 g/L dry biomass with 15% of intracellular lipid content (1.2 g/L) in a 170 h-long batch culture.