Preliminary Study On Antifungal Antibiotics CA-SD07Fermentation Production

Fungal infection is a common disease, which brought a lot of harm to people’s life. At present, utilization of antifungal drugs is the main method to cure fungal infection. However, their therapeutic use is often hindered by problems such us acquired drug-resistance and strong toxicity. Therefore, finding new antifungal antibiotics of small side effects and high bactericidal activity has been the hot topic in the field of microorganism and medicine.Polyene macrolide antifungal drugs can be directly combining to ergosterol of fungal cell membrane, increase the cell membrane permeability and result in cell lysis at last. Streptomycese netropsis SD-07strains which isolated by our laboratory in2007, can produce new polyene macrolide antifungal antibiotics, which with very higher antifungal activites. This thesis is a preliminary study on polyene macrolide antifungal antibiotics fermentation production from Streptomycese netropsis.The thesis consists of fermentation process optimization in the production of antibiotics and preparation process optimization, purification, analysis.1. Optimization of fermentation processThe Plackett-Burman design and central composite design (CCD) test method of mathematical statistics was used to optimize the composition of the fermentation media. Finally, we got a better fermentation media which with suitable composition. The fermentation yield increased to1.5times when using optimized fermentation medium. Through the primary and secondary screening of the total78strains in our laboratory, finally we got three high-yield strains, named as180,163-12,919.Based on many times of5L tank fermentation and triangle flask fermentation with high yield strain, the optimal fermentation medium was proved. At the same time, in terms of fermentation parameters, the following results and conclusions reached: Triangle bottle place in the table have obvious effects on the fermentation results, especially near the hot air-port, can significantly reduce the fermentation production. In5L and50L fermentation tank, the fermentation parameter analysis and magnified comparison was made, which provides reference for the factory production and the preparation of a large number of mycelium (3351.3g) to be used for extraction of antibiotics.2. The preparation process optimization, purification and analysisPreparation and separation of fermented product by ethanol extraction, concentration, crystallization, organic solvent washing methods, such as system comparison of two kinds of preparation methods to produce antibiotics titer of coarse product, yield and activity, purity and other indicators, the results showed that:from simple and crude products final titer and yield point of view, the No.1preparation method is better; from higher purity of view, the No.2preparation method is better.To the antibiotic crude products, through the analysis of purified by LH20(molecular sieve gel) and intermediate pressure chromatography (Silia Bong C18column) two methods, we can got our target antibiotics peaks. In comparison, the medium pressure chromatography has more advantages because of its higher sample weight, speediness and simpleness. Through the analysis and purification of antibiotic raw products, we preliminary got the semi-finished products of antibiotics (995.2mg), for the future to antibiotic CA-SD07structure fine resolution as a material basis.