Fig. 7.

Optimized process design for lipid production using model 3. This diagram shows the rational design of carbon and nitrogen feed when acetate concentration is maintained at zero in the system. RQ threshold is set at 1.2 to trigger the start of RQ and CTR feedback control. Decrease in RQ implies only an insufficient lipid synthesis, indicating a nitrogen overfeed, whereas decrease in both RQ and CTR implies a flux diversion toward undesired pathways, indicating the need for an increased nitrogen feed. α = 0.05.