Metabolic Regulation And The Researches On Submerged Fermentation Of A Berberine-Producing Endophytic Fungus

The strain is an endophytic fungus isolated from Amur cork, and the mutant strain S-NU-41 with high yield of bioactive compound berberine was obtained by mutation breeding. To improve the yield of berberine, various factors that may affect were investigated. subsequently, the fermentation conditions in 5 L-fermentor were studied. This research provides a theoretical basis for the industrial fermentation production of berberine.To select the optimal concentration that could stimulatine the yield of berberine, different concentrations of Amur cork extract and metal ions were added in the culture medium. After that, the fermentation conditions for the production of berberine in shake flask and 5L-fermenter were optimized, some batch fermentation and fed-batch fermentation conditions in 5 L-fermentor were studied.The yield of berberine were effectively improved by adding 1% Amur cork extract (increased by 26.2% compared with the control), and the hypha growed better by adding 5% Amur cork extract.The yield of berberine can be improved by adding different metal ions including K+, Ca2+, Fe3+, Mn2+, Zn2+, Cu2+ and Mg2+, among them, Zn2+ and Mg2+ have a better role, and the yield of berberine increased by 24.5% and 24.4%, respectively. In addition, we found that it was inhibited by Co 2+.The appropriate feeding time and quantity were investigated in flask-shaking fed batch fermentation, and the results showed that the optimum time for feeding carbon sources, nitrogen sources, medium and precursor were 30 h,42 h,30 h and 42 h, and the feeding quantity was 30 g/L,4 g/L, medium with optimized C/N and lmg/L, and the concentration of berberine in culture media increased by 16.0%,19.5%,25.0% and 28.2%, respectively.The fermentation laws of the strain S-NU-41 in 5 L-fermentor were studied. By increasing the dissolved oxygen of the culture media at the exponential phase, the time to reach berberine peak was shortened by 6 h, the dry weight of mycelia was increased by 217.9% evidently, and the yield of berberine could reach 1.946 mg/L. On the basis of the shake-flask fermentation research, the fed-batch fermentation conditions were investigated, the results showed that the yield of berberine increased 26.8% and 29.2% by using intermittent fed-batch, and the fed-batch feeding strategy of adding carbon sources and medium was at intervals of 2 h from 30 h to 36 h in the fermentation process. In the continuous fed-batch process by adding nitrogen sources and precursor, the yield of berberine was 13.5% and 39.7% higher than that in the batch fermentation. Therefore, the yield of berberine was improved greatly by adding medium and precursor.