Stugdy On The Breeding And Fermentation Process Optimization Of CTC-Pproducing Strains

In this study, the Streptomyces aureofaciens and the secondary metabolite CTC were taken as the objects of study. UV and lithium chloride (LiCl) were used for the compound mutation to screen the high-producing strains. Through the flask-shaking experimental study on the influence of the peptone’s displacing and adding the metal ions and the fast or low utilization of carbon source on CTC fermentation, the impact of different factors, such as, the temperature, incubation period, feeding method, on the growth and metabolism of the Streptomyces aureofaciens, was analyzed. Taken50L,6m3and180m3fermentor incubation methods as the major incubation methods, the productive power of mutant strains was tested and verified; the frequency conversion control technology of fermentation system was taken to analyze the impact of the stirring speed and stirring paddle on the dissolved oxygen and titer in CTC fermentation process. Through the above research method, it can be concluded as follows:after the compound mutation of UV and Licl,1stable high-yield mutant strain F3can be screened from the original strains D29; and the flask-shaking titer can achieve25502μg/ml, which was higher by10.8%than that of the original strains. Through the experiment, it can be confirmed that the seed page of strain was22-24h, the appropriate incubation temperature was29℃and the continuous flow feeding in the feeding methods was better. After72h fermentation, when1ppm iron ion or200ppm magnesium ion was added, the titres of ferment liquor separately rose by4.3%and7.3%. In CTC fermentation medium, the adding proportion of peptone was1.0%and the titer was the highest, and then the substitute products and proportions of peptone were generated, the results was that the50%of soybean flour,70%of com steep liquor and groundnut flour displaced the peptone, which could make the fermentation level increase by7.6%,5.7%and5.2%separately. After the glucose displaced the15%of corn starch to sterilize, it was supplemented into the fermentor, which obviously reduced the pH value of previous fermentation liquor and could make the fermentation titer maintain at the normal level. Through the fermentation experiments of mutant strain F3in50L,6m3and180m3fermentors, the superiority on the productive power was obvious that can confirmed. The frequency conversion equipment was used to control the stirring speed of6m3fermentor, the electricity consumption per single batch was1446Kw on an average; compared to the constant stirring, the energy-saving rate was18%. The research results above would have an important guidance function on actual production.