Figure 6.
Flux partitioning around the leucine metabolism at 8 mg l−1 phytosterols and three different levels of assimilable nitrogen.
The distribution of fluxes around these metabolic routes was investigated using isotopic filiation experiments with 13C‐labelled leucine. Portion of consumed leucine recovered in proteinogenic leucine: the labelled fraction (light colour) corresponds to the consumed leucine directly incorporated into proteins, while the unlabelled fraction (dark colour) represents the proteinogenic amino acids de novo synthetized from CCM precursors. Portion of consumed leucine converted into volatile compounds: the labelled fraction (light colour) corresponds to the fraction of volatile compounds synthetized using carbon from consumed leucine, while the unlabelled fraction (dark colour) represents the portion of volatile molecules synthetized from α‐ketoacids through the CCM. Flux partitioning involved in the use of leucine during fermentation: the fraction of consumed leucine catabolized through a certain pathway was assessed from the molar ratios between the amount of a proteinogenic amino acid or volatile compound labelled and the total amount of consumed amino acid. Isotopic enrichments (defined as the molar ratio between the quantity of labelled compound and the total quantity) are shown above each bar plot. The raw data and details of the calculations are provided in the Supplemental Material. Blue: SM70; orange: SM250; pink: SM425.