| We optimized the carbon source and nitrogen source in the fermentation medium, and the condition of culture; selected the precursors and inorganic salts which are beneficial to the production of natamycin, observed the quantity of precursors and inorganic salts effect on the titre of natamycin. In the the fermentation of natamycin, we tested carbon source, nitrogen source, Plackett-Burman experiment, steepest ascent experiment, central compose experiment and response surface experiment. The result of these experiments were as follows:glucose was 4%, potato starch was 2%, soybean cake powder was 1.65%, yeast extract was 0.76%, magnesium sulfate was 0.05%, calcium carbonate was 0.2%, n-butanol was 0.05%. Under the condition of optimized fermentation medium, the titre of natamycin could reach 2285.72μg/mL. It increased 71.8% than the original culture medium. In the processes of optimizing culture condition, table rotational speed, primary pH, flask column, innoculation content and fermentation time on fermentation had been studied. The result showed that the table rotational speed was 190r/min, primary pH was 8.0, flask column was 25mL/250mL, innoculation content was 8%, fermentation time was 96h.Based on the results of fermentation in 250mL shake flasks, natamycin fermentation was scaled up in a 16L fermentor. The metabolic characteristics of natamycin-producing strain were investigated in the 16L fermentor. We used the fed-batch fermentation with intermitted culture, fermentation period was 192h. We added 50% glucose solution to fermentation medium from 44h beganing. We made up sugar every 6h, and keep sugar concentration on 20g/L. The titre of natamycin reached the maximum when 168h. At the time, pH was 4.55, content of reducing sugar was 29g/L, content of total sugar was 36g/L, biomass was 38g/L, and the titre of natamycin in fermentation pot was 4550.72μg/mL. Key words:natamycin; fermentation; culture medium; precursor; glucose feeding...
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