Fig. 5

Dynamic FBA simulation of lipid accumulation in N. salina using iNS934. We simulated growth and lipid production using COBRA tools in three stages: NO₃ available, NO₃ depleted and NO₃ available again. a NO₃ available in the media. We set an initial amount of NO₃ that was consumed by N. salina and eventually depleted. After this event, we added NO₃ to the media, allowing N. salina to grow normally again. b Biomass accumulation of N. salina. After NO₃ depletion, biomass production was reduced in stage 2 and increased again in stage 3. c Total lipid production (including TAG). In the first stage, lipid production increases according to the stoichiometric coefficients in the biomass formation reaction. Once NO₃ is depleted, the lipid production increases in a higher rate than stage 1 due to the high amount of TAG produced toward lipid bodies. In stage 3, the lipid production rate is once again as described in stage 1. d TAG accumulated on lipid bodies. We created a compartment called “lipid bodies”, where the TAG produced, and not consumed by biomass, was stored