Fermentation And Extract Technology Of Natamyci

Some primary researches were done on fermentation and extract technology of natamycin by Streptomyces natalensis.First of all, determination method of natamycin was established. The yield of natamycin and the diameter square of inhibitory zone took on a good linear relation after the determination of parameter of agar diffusion method. To determine the concentration of natamycin exactly, the concentration of standard was estimated initially by one-dosage method. Results of two-dosage method based on one-dosage method compared with HPLC had a relative error less than 5%, which demonstrated that natamycin bioassay was credible.A natural mutant Streptomyces natalensis 8B with streptomycin resistance character was selected for its stable heredity by agar block method. And the yield of 8B was up to 1023 mg/L, which was 36 percent higher than initial strain.The optimum medium and fermentation conditions for natamycin production were demonstrated by application of response surface analysis. The optimum medium consisted of (g/L): potato starch 61, bean cake powder 42, yeast extract powder 5, KH₂PO₄ 1, and CaCO₃ 2, pH 7.0. Inoculum volume was 2%. A 500 mL flask containing 80 mL medium was cultivated at 28℃ for 96 hours and the speed was 180 r/min. The yield of natamycin under these conditions was 1636 mg/L, which was 60 percent higher than the one before optimization.After flocculation by chitoson whose concentration was 0.12 percent, the broth and mycelium were separated. Intracellular natamycin was extracted by organic solvent. And the part in the broth was enriched by macroreticular resin DM11. The intracellular and extracellular extraction rates were 78% and 95%.By identification of Ultra absorption chromatogram, FT-IR spectra, H-MS chromatogram and HPLC, the structure of sample and standard was consistent basically. And the intracellular and extracellular purifications of production were 92.4%, 95.6% separately.