Optimization of fermentation conditions for EplT4 production by pichia pastoris expression system using response surface methodology

The design of the optimum conditions for production of EplT4 protein from Trichoderma asperellum T4 in Pichia pastoris expression system was performed using response surface methodology (RSM). Temperature, pH and Basal Salts were the most important experiment factors selected by Plackett-Burman design. Afterward, the optimal combination of the three factors and the corresponding maximum yield of EplT4 protein were explored using Box-Behnken Design. As shown in the results, the maximum EplT4 protein yield of 38.03 mg/L was predicted when temperature, pH and Basal Salts were 28.5°C, 4.7 and 62.7%, respectively. The maximum yield of 37.70 mg/L EplT4 was obtained under the optimum conditions, which verified the practicability of the optimum method. These results indicated that EplT4 yield was remarkably improved through optimizing the P. pastoris expression system using response surface methodology. Furthermore, the obtained EplT4 recombinant protein was proved effective to induce defense responses in soybean. Therefore, this study is meaningful for the application of EplT4 as a promising biofungicide.