Study On Component Optimization And Fermentation Control Of Kitasamycin Biosynthesis

In this study,metabolism of Streptomyces kitasatoensis was studied by the addition of several chemicals in order to enhance the synthesis of kitasamycin.Adding glycerol in the shake flasks showed that 4%of soybean oil and 0.68%of glycerol could increase the titer of kitasamycin by 24.1%.Studies on 5 L fermentor showed that adding 0.68%glycerol at 16 h resulted in kitasamycin titer of 10463 U/mL(increased by 18.4%).In this case,the content of A5 component was 60.2%(increased by 6.1%).The content of A1 component was 4.6%(reduced by 3.9%).With respect to kitasamycin titer,methyl linoleate or methyl oleate was better than linoleic acid or oleic acid.Soybean oil could improve kitasamycin titer due to the combined effect of two components,but the detailed mechanism of work remained to be explored.From the component changes of shaking flask fermentation and 15 L tank fermentation of methyl oleate,it was easy to find that the addition of methyl oleate,methyl linoleate,the content of A5 component had improved significantly,A4 component decreased,A1 component had no obvious change.Soybean oil contained some trace materials which may transform the A5 into A4.It is of great significance to optimize kitasamycin production based on the addition of these chemicals.Study on the influence of sodium acetate,ethyl acetate on kitasamycin titer in the shake flasks.We found that when adding 0.15%sodium acetate or 0.48%ethyl acetate,kitasamycin titer was increased by 6.2%or 18.8%respectively.In 15 L fermentor,adding sodium acetate at 112 h resulted in the draw-off titer of 7109 U/mL.However,the draw-off titer of the control and ethyl acetate at 102 h were 8725 U/mL and 10546 U/mL respectively.When 0.48%ethyl acetate was added in fermentation medium,kitasamycin titer was increased by 21%,A5 content was increased by 5.1%.Nevertheless,A1 component had no obvious change.But the addition of sodium acetate lowered the titer and extended production period.