Medium Optimization for GA4 Production by Gibberella fujikuroi Using Response Surface Methodology

Gibberellin is an important plant growth regulator that has been widely used in agricultural production with great market prospects. However, the low yield from Gibberella fujikuroi restricts its application. To improve the production of gibberellin A4 (GA4), the response surface methodology was used in this study to explore the effect of different types and concentrations of vegetable oil and precursors on the production of GA4. Based on a single factor experiment, the Behnken box and central composite designs were used to establish the fermentation condition model, and the response surface method was used for analysis. The results indicated that the optimum formula was 0.55% palm oil, 0.60% cottonseed oil, 0.64% sesame oil, 0.19 g/L pyruvic acid, 0.21 g/L oxaloacetic acid, and 0.21 g/L citric acid for 48 h, which produced a yield 4.32 times higher than that without optimization. This suggests that the mathematical model is valid for predicting GA4 production in Gibberella fujikuroi QJGA4-1.