De Vicente, MartaGonzalez Fernández, CristinaNicaud, Jean MarcTomás Pejó, Elia2025-03-062025-03-062025de Vicente, M., Gonzalez-Fernández, C., Nicaud, J.M. et al. Turning residues into valuable compounds: organic waste conversion into odd-chain fatty acids via the carboxylate platform by recombinant oleaginous yeast. Microb Cell Fact 24, 32 (2025). https://doi.org/10.1186/s12934-025-02647-71475-285910.1186/s12934-025-02647-7https://hdl.handle.net/20.500.14352/118572This work has been supported by the Spanish Ministry of Economy and Competitiveness through the grand RYC2019-027773-I, BIOMIO (PID2020-119403RB-C21) supported by MCIN/AEI/https://doi.org/10.13039/501100011033 and the Ministry of Science and innovation for the predoctoral contract for the formation of future doctors (FPI 2021) (PID2020-119403RB-C21).Environmental concerns are rising the need to find cost-effective alternatives to fossil oils. In this sense, short-chain fatty acids (SCFAs) are proposed as carbon source for microbial oils production that can be converted into oleochemicals. This investigation took advantage of the outstanding traits of recombinant Yarrowia lipolytica strains to assess the conversion of SCFAs derived from real digestates into odd-chain fatty acids (OCFA). High yeast OCFAs content was aimed by using two engineered strains (Y. lipolytica JMY7780 and JMY7782). Batch and two-step batch fermentations were performed, reaching high lipid content (40.8% w/w) and lipid yield (0.07 g/g) with JMY7782, which overexpresses propionyl-CoA synthase. Fed-batch fermentation with an acetic acid pulse after 24 h was also carried out to promote SCFAs consumption and OCFAs production. In this case, SCFAs consumption rate increased and JMY7782 was able to accumulate up to 60.4% OCFAs of the total lipids produced from food waste-derived carbon sources.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal articlehttps://doi.org/10.1186/s12934-025-02647-7https://microbialcellfactories.biomedcentral.com/articles/10.1186/s12934-025-02647-7open access577.166.09Short-chain fatty acidsYarrowia lipolyticaLipidsOdd-chain fatty acidsOleaginous yeastsBioquímica (Biología)Biotecnología2403 Bioquímica2302.21 Biología Molecular3302.90 Ingeniería Bioquímica