Metabolic modelling and energy parameter estimation of Tetradesmus obliquus

We developed a metabolic network describing the primary metabolism of Tetradesmus obliquus aimed to get a better understanding of metabolism to improve industrial production. The network includes 351 reactions with 183 metabolites distributed over 4 compartments: cytosol, chloroplast, mitochondria, and extracellular space. The energy requirements for biomass assembly and maintenance (K_x and m_ATP, respectively) were experimentally determined from batch cultures and included in the model. The determined values were 121.02 mmol_ATP·g_DW ⁻¹ for K_x and 0.66 mmol_ATP·g_DW ⁻¹·h⁻¹ for the m_ATP. The maintenance value found for T. obliquus is, to our knowledge, one of the lowest reported in literature for microalgae. This low value is also in agreement with the photon maintenance requirement found experimentally for T. obliquus (1.18 mmol_ph·g_DW ⁻¹·h⁻¹). Finally, the theoretical maximum yields based on the model for biomass, triacylglycerides (TAG), and starch yield on light were calculated to be 1.15 g·mol_ph ⁻¹, 1.05 g_TAG·mol_ph ⁻¹, and 2.69 g_starch·mol_ph ⁻¹.