| Strain breeding and fermentation process of flavomycin were studied in thisarticle. Compared to flavomycin potency levels in2010, these studies achievedmeaningful results: potency in shaking flask phase is increased by2355u/mL; potencyin50-L fermentation tank phase is increased by1647u/mL.Firstly, a concentration is established in which flavomycin strains are resistant totheir metabolitic products. Study the mutagenic effect of parent strains via nitrogenion implantation method. An appropriate nitrogen ion implantation dosage is chosenvia study the fatality rate and positive mutation rate caused by different dosage ofnitrogen ion implantation. By means of preliminary screening and secondscreening, a high-yield strain is achieved, which possesses good genetic stability.Secondly, the medium formula prepared for above achieved high-yield strain isoptimized. The optimum medium formula is confirmed as following: glucose:4%,corn steep liquor:3%, soybean powder:1%, K2HPO4:0.20%, NaCl:0.3%, MgSO4:0.06%, CaCO3:0.03%; organosilicon antifoamer:0.12%. Three critical factors andtheir concentrations are drawn by means of PB design and response surfaceexperiments: glucose:5.56%, corn steep liquor:1.15%，soybean powder:2.56%。Moreover, we optimize fermentation conditions （temperature, liquid volume, pH,seed age, inoculation amount, rotational speed, etc.） of flavomycin producing strain,and the best fermentation condition: temperature:37℃, liquid volume:100ml, pH:5.0, seedage:26h, inoculation amount:10%, rotational speed:210rpm. ByPlackett-Burman experimental design and Response Surface experimental design,three important technological conditions which influence fermentation potency offlavomycin are determined: temperature:37℃, seed age:29h, inoculation amount:12.5%.At last, flavomycin producing strain pilot experiment was performed in50-Lfermentation tank, and the optimized fermentation conditions were confirmed asfollowing: stirring speed:200rpm, ventilation:2vvm-1. |
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