Study On L-Ornithine Fermentation Condition And Analysis Of Fermentation Kinetics

L-ornithine is an intermediate metabolite in arginine biosynthesis. It is effective in the treatment of liver disorders and helps strengthen the heart. For these reasons, it has a sizable world market. According to the theory of metabolic control fermentation, the dissertation focuses on fermentation condition of L-ornithine producing strain1006 and how to control the fermentation process. The main research contents and results are as follows:(1) A method of HPLC-ELSD was established using Prevail C18 column for the determination of L-ornithine. The mobile phase was 0.06% HFBA in water- acetonitrile (88∶12) , with a flow rate of 0.8 mL/min at 30℃. The temperature of drift tube heater was 110℃and the gas was flowing at the rate of 2.8 L/min. A good linearity was obtained in the range of 0.1–0.6mg/mL (R²= 0.9998) for L-ornithine. The average recovery of L-ornithine was 98.94 %. The method is simple and rapid with reproducibility for the determination of L-ornithine in the fermentation broth.(2) The batch fermentation condition of strain1006 in shake flask was investigated. The proportions of seed medium and fermentation medium were optimized by Box-Behnken design experiment and central composite design with response surface analysis method. The optimum fermentation medium was as follow (g/L): glucose 80.50, yeast extract 20.50, (NH₄)₂SO₄ 53,MgSO₄·7H₂O 3.70, K₂H PO₄·3H₂O 1.50,CaCO₃10,FeSO₄·7H₂O 18.30mg/L,MnSO₄·H₂O22.38mg/L,Biotin0.05 mg/L,VB10.1mg/L. The optimized fermentation condition was as follow: the initial pH value was 7.2, the fermentation medium size was 30mL in the flask of 500mL, the rotated speed of flask was 200r/min and the fermentation temperature was 30℃. Under the optimum condition, L-ornithine yield was up to 33.59g/L by strain1006 after fermentation for 72h by flask-shaking batch fermentation.(3) The L-ornithine batch fermentation process of strain1006 in 5-liter...