Improving Gibberellin GA 3 Production with the Construction of a Genome-Scale Metabolic Model of Fusarium fujikuroi .

Liquid fermentation is the primary method for GA 3 production using Fusarium fujikuroi . However, production capacity is limited due to unknown metabolic pathways. To address this, we constructed a genome-scale metabolic model ( i CY1235) with 1753 reactions, 1979 metabolites, and 1235 genes to understand the GA 3 regulation mechanisms. The model was validated by analyzing growth rates under different glucose uptake rates and identifying essential genes. We used the model to optimize fermentation conditions, including carbon sources and dissolved oxygen. Through the OptForce algorithm, we identified 20 reactions as targets. Overexpressing FFUJ_02053 and FFUJ_14337 resulted in a 37.5 and 75% increase in GA3 titers, respectively. These targets enhance carbon flux toward GA 3 production. Our model holds promise for guiding the metabolic engineering of F. fujikuroi to achieve targeted overproduction. In summary, our study utilizes the i CY1235 model to understand GA 3 regulation, optimize fermentation conditions, and identify specific targets for enhancing GA 3 production through metabolic engineering.