The Metabolic Modeling and FBA Server also enables users to run various FBA studies on any of the genome-scale metabolic models stored in the SEED database. These studies can be performed while simulating any of 525 distinct media conditions currently encoded in the SEED database (which includes all BiologH [30] media conditions and a variety of complex media formulations). Both the Perl program and the API enable users to obtain a list of the media conditions currently stored in the SEED and details on the compounds included in each formulation. Once a model and media condition have been selected for simulation, the server provides an interface for running three types of FBA simulation: (i) simple growth simulation to predict maximum growth rate of the organism in the selected media, (ii) flux variability analysis (FVA) [31] to classify the reactions and compounds in the model according to their behavior during growth in the selected media, and (iii) single gene knockout analysis to predict the genes essential for growth in the selected media.