Fig. 4.

A schematic of constraint-based modelling using flux balance analysis (FBA). The allowable solution space, which contains all possible flux distributions, is constrained by mass balance, thermodynamics, and capacity constraints. The red dot on the edge of the solution space represents an optimal flux solution for the specific objective function $Z$. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)