Biological Preservative Natamycin To Produce The Fermentation Process

26-membered ring polyene macrolide antibiotics natamycin can effectively inhibit the growth of yeast and mold,which serves as a broad-spectrum antifungal agent and it's effective in the therapy of medical treatment and protection of foods. In this paper, some systematic researches were done on fermentation of natamycin by Streptomyces natalensis HDMNTE-01, determination method of natamycin, the optimization of medium composition and fermentation conditions were studied emphatically.First of all, detection 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, equation of linear regression: y=0.0013x-1.3369,R2=0.9965. One high yield strain No.103 was screened from different colony shape by agar block method and shaking flask fermentation. The yield of natamycin in shaking flask was 0.59g/L.The batch fermentation of natamycin production of strain No.103 in shake flask was studied,and the optimal condition of simplex factors fermentation were achieved. Seed medium:glucose1.0%, amylon1.0%, soybean cake power1.0%, peptone0.6%, corn steep liquor0.6%, MgSO4·7H2O 0.1%,K2HPO4 0.05%,NaCl0.2%,CaCO30.5%,pH7.0, inoculum volume was 6%, cultivated at 29℃for 96h and the agitation speed was 220r/min; carbon source:glucose4%; nitrogen source and their proportion: soya peptone 2%+yeast extract 0.5%; DO: 250mL flask containing 25mL medium, agitation speed was 220r/min; initial pH value: 7.0; temperature: 28℃; the regulation of metabolism: adding 0.003% ferrocyanatum Kalium into the broth at 0h and 0.4% n-butanol at 24h of cultivation.According to the preliminary study of batch shaking-flask fermentation, Response Surface Methodology was applied to optimize the zymotechnique of natamycin, and the optimum zymotechnique were achieved. Medium consisted of glucose3.97%, soya peptone 2%, yeast extract 0.5%, the pH of the medium was 7.0 and inoculum volume was 6%. A 250mL flask containing 24.68mL medium was cultivated at 29℃for 96h and the agitation speed was 220r/min, adding 0.003% ferrocyanatum Kalium into the broth at 0h and 0.4% n-butanol at 24h of cultivation. The yield of natamycin was up to 1.471g/L under the optimized conditions, which was 149% higher than the one before optimization.A 5L bioreactor was used to study the magnicication of natamycin fermentation, the productivity of natamycin reached 2.4g/L in the optimized operating conditions, which was 63% higher than that in shaking-flash fermentation.