Flux Balance Analysis
Flux balance analysis (FBA) is a constraint-based method for predicting steady-state metabolic flux distributions in cells. Given a genome-scale metabolic model and an objective function (usually growth or target compound production), FBA solves a linear programming problem to find the flux distribution that maximizes the objective while satisfying mass balance and thermodynamic constraints.
The Stoichiometric Framework
Every metabolic reaction has a stoichiometry — fixed ratios of consumed and produced metabolites. FBA encodes thousands of reactions as a matrix S and seeks a flux vector v such that S·v = 0 (steady-state mass balance) and each flux is bounded by enzyme capacity or thermodynamic limits. Linear programming finds the feasible v that maximizes the objective.
Application to Capsaicin Engineering
When the capsaicin biosynthesis cassette is moved into a new host (tomato, rice, basil), FBA predicts whether the host metabolic network can supply sufficient precursor flux through both the phenylpropanoid and branched-chain fatty acid branches simultaneously. It also identifies competing pathways that drain shared precursors — pointing to knockouts or overexpressions that would increase yield.
Every Scoville Splice construct includes an FBA report with predicted yield range, competing pathway analysis, and supplementary edit recommendations.