Flux Balance Analysis uses stoichiometric relationships to write a mass-balance equation for each internal metabolite. At steady state, production and consumption are balanced, so the model excludes net accumulation within those pools. Linear programming then searches among flux rates that satisfy these equations, providing a mathematically consistent way to examine how metabolic activity can be distributed through the network.
The objective selects which feasible flux distribution the calculation prioritizes. Biomass production can represent a growth-focused cellular state, whereas another explicitly defined objective would emphasize a different modeled outcome. Because the network constraints may allow multiple consistent allocations of reaction rates, changing the objective can change the predicted flux pattern and its biological interpretation.
Inputs describing nutrient availability or environmental conditions change the constraints under which the network is evaluated. Similarly, a gene or pathway change can alter the represented reaction capabilities. The resulting optimization may predict differences in growth, nutrient use, or by-product formation, allowing researchers to compare how the modeled cell reallocates metabolic resources across conditions.
Steady-state treatment focuses the calculation on internal metabolites whose pools are considered balanced over the modeled interval. This assumption connects reaction rates through stoichiometry and prevents the solution from representing unexplained accumulation or depletion inside the network. The resulting flux distribution describes a sustained metabolic state, which is useful when comparing growth or resource-allocation predictions across defined conditions.
First, represent the relevant metabolism as a stoichiometric network linking reactions and metabolites. Next, impose steady-state mass-balance constraints on internal metabolites and specify the condition or objective to optimize, such as biomass production. A linear-programming calculation then identifies compatible reaction-rate distributions, which can be examined for predicted growth, nutrient use, or by-products.
It helps compare candidate metabolic states and examine how pathway or gene changes could affect cellular performance. Predicted growth, nutrient consumption, and by-product formation can guide analysis of strain designs, while the network perspective shows how altering one pathway may influence resource allocation elsewhere. This makes the method relevant to designing and evaluating engineered biological systems.