Dynamical metabolic modelling for lipid accumulation by Yarrowia lipolytica growing on glucose

The oleaginous yeast Yarrowia lipolytica has been extensively studied due to its capacity to accumulate great amounts of lipids triggered by the excess of the carbon source and the limitation of nitrogen. However, under these conditions this yeast can also produce citric acid, which decreases lipid conversion yield. Few dynamical models are only available to describe lipid metabolism based on mass balances and different kinetic configurations. Nevertheless, cybernetic modeling has allowed extending optimization through the inclusion of internal regulation to identify the controlling steps and metabolic fluxes. In the present work a dynamic metabolic model was developed and applied with two variations, and was compared with experimental data carried out in fed-batch cultures of yeast Y. lipolytica on glucose as carbon source. Two independent data sets regarding nitrogen limitation and deficiency were used for parameter estimation. Results show a good fit of parameters on describing the dynamics of lipids and citric acid production.