## 4 Conclusions  
Agro-food wastes and lignocellulosic urban pruning residues exhibit high potential as sugar-rich feedstock for microbial-based processing. In this context, the yeast _R. toruloides_ was capable of accumulating up to 45% of its dry weight of intracellular lipids and 665 \(\upmu\)g/g of carotenoids when using the corresponding waste-derived streams as culture media under a pulse-feeding strategy. With the aim of improving the process productivity values, the agro-food waste stream was concentrated to increase the initial nutrient concentration. This strategy allowed complete sugar consumption within 96 h without the need for external nutrient supplementation, increasing final cell biomass concentration, lipid concentration, and carotenoid concentrations up to 55.5 g/L, 23.3 g/L, and 736 \(\upmu\)g/g, respectively. In contrast, the sugar-to-lipid conversion yields and the storage lipids percentage decreased from 0.25 g/g and 43.5% to 0.20 g/g and 35.7%, respectively, as indicative of the lower stress pressure caused on yeast cells from the nutrient-limiting conditions. Overall, these results show great potential to provide effective alternative uses to current biowaste man  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Growth Medium** & **Process Time** & **Torulardoin** & **Torulene** & \(\upgamma\)**-Carotene** & \(\upbeta\)**-Carotene** \\ \hline \multirow{3}{*}{Agro-food waste stream} & Before 1 st pulse & 62 \(\pm\) 4 & 115 \(\pm\) 7 & 109 \(\pm\) 2 & 62 \(\pm\) 8 \\  & Before 2 nd pulse & 68 \(\pm\) 5 & 141 \(\pm\) 4 & 106 \(\pm\) 6 & 43 \(\pm\) 3 \\  & Final & 94 \(\pm\) 4 & 289 \(\pm\) 6 & 100 \(\pm\) 8 & 40 \(\pm\) 3 \\ \hline \multirow{3}{*}{Concentrated agro-food waste stream} & Before 1 st pulse & 72 \(\pm\) 8 & 166 \(\pm\) 6 & 145 \(\pm\) 4 & 71 \(\pm\) 3 \\  & Before 2 nd pulse & 119 \(\pm\) 5 & 211 \(\pm\) 4 & 127 \(\pm\) 5 & 61 \(\pm\) 4 \\  & Final & 132 \(\pm\) 16 & 341 \(\pm\) 11 & 103 \(\pm\) 21 & 59 \(\pm\) 12 \\ \hline \end{tabular}
\end{table}
Table 4: Carotenoid profile at different time points during the cultivation of _R. toruloides_ ATCC 204091 in the non-concentrated and concentrated agro-food waste streams as growth media following a pulse-feeding strategy with the enzymatic hydrolysate of a lignocellulosic urban residue to trigger lipid accumulation. Data in \(\upmu\)g/g DCW.  
agement practices, also contributing to placing industrially relevant products with lower environmental impacts in the market.  
Conceptualization, M.J.N.; formal analysis, A.R.-L., J.L.F.-R. and I.B.; investigation, A.R.-L., J.L.F.-R. and I.B.; data curation, A.R.-L., M.J.N. and A.D.M.; writing--original draft preparation, M.J.N. and A.D.M.; writing--review and editing, M.J.N., I.B. and A.D.M.; supervision, M.J.N.; project administration, M.J.N.; funding acquisition, M.J.N. All authors have read and agreed to the published version of the manuscript.  
This research was funded by MCIN/AEI/ (10.13039/501100011033, project BIOMIO+CAR, grant number PID2020-119403 RB-C22).  
Not applicable.  
The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.  
Fundacion Cajamar (Almeria, Spain) and CEDER-CIEMAT (Soria, Spain) are greatly acknowledged for providing the agro-food and the lignocellulosic urban pruning residues used in this study.  
The authors declare no conflicts of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} C/N & Carbon/nitrogen ratio \\ DCW & Dry cell weight \\ FAs & Fatty acids \\ FAMES & Fatty acid methyl esters \\ SCO & Single-cell oil \\ \end{tabular}