สภาวะที่เหมาะสมสำหรับการผลิตจิบเบอเรลลินในถังหมัก / อรไท สุขเจริญ = Optimal condition for the production of gibberellins in fermentor / Oratai Sukcharoen
The scope of this work is to study the optimal conditions for the production of gibberellin GA₃ by Gibberella fujikuroi C in a 5-L fermentor. The optimal conditions for the production of gibberelling GA₃ by Gibberella fujikuroi C in a 5-L fermentor were determined. The suitable medium compositions for the production of GA₃ contained perlitre, 100 gm. Of sucrose as carbon source, ammonium sulfate and defatted soybean meal with the nitrogen content of 0.40 and 0.14 gm., respectively as nitrogen sources, 5 gm. Of potassium dihydrogen phosphate, 1 gm. Of magnesium sulfate, 0.1 gm. Of aluminium oxide as minerals, and 0.2 ml of soya bean oil as an enhancing substance. The medium was adjusted to pH 7 before autoclaving. The optimal cultivation conditions were as follows : cultivation temperature at 25̊C, the aeration rate at 1.0 vvm. And the agitation speed at 500 rpm. Continuous feeding of glucose was started at 162 hours of cultivation and its concentration was maintained at 25 g/l throughout the period of fermentation. The pH of the medium was uncontrolled. Under these conditions, 1023 mg/l of GA₃ was obtained at 348 hours of cultivation, dry weight 25.5 g/l and the mean GA₃ production rate was 3.05 mg/l/hr. By monitoring the contents of carbon and nitrogen sources including dissolved oxygen remained in the medium during the fermentation, the limiting factor for GA₃ production was neither carbon source, nitrogen source nor dissolved oxygen, but it was due to the weakness of the cell itself.
