Optimisation of the biological production of levulinic acid in a mixed microbial culture fed with synthetic grape pomace Correa Galetote, David Serrano Moral, Antonio Ciudad, Gustavo Pinto-Ibieta, Fernanda biological production feast and famine grape pomace hydrolysate Levulinic acid (LA) is a polymer with a vast industrial application range and can be co-produced as a minor by-product during the biological production of polyhydroxyalkanoates (PHA). However, the influence of key parameters as tools for favouring the production of LA over PHA is still unclear. In this study, we investigated how several critical operational conditions, i.e., carbon-nitrogen ratio (C/N), organic loading rate (OLR) and airflow, can be optimised to favour LA accumulation over PHA production by a mixed microbial culture (MMC), using synthetic grape pomace (GP) hydrolysate as the substrate. The results showed that it was possible to direct the MMC towards LA accumulation instead of PHA. The maximum LA yield was 2.7 ± 0.2 g LA/(L·d) using a C/N of 35, an airflow of 5 L/ min and an OLR of 4 g sCOD/(L·d). The OLR and, to a lesser extent, the C/N ratio were the main factors significantly and positively correlated with the biological synthesis of LA. 2024-07-19T11:05:57Z 2024-07-19T11:05:57Z 2024-05-10 journal article Correa Galetote, D. et. al. Volume 12 - 2024. [https://doi.org/10.3389/fbioe.2024.1398110] https://hdl.handle.net/10481/93268 10.3389/fbioe.2024.1398110 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Frontiers