Growth Characteristic For Streptomyces Ghanaensis And Fermentation Technology Of Flavomycin

Flavomycin is a member of the phosphoglycolipid family of antibiotics produced by Streptomyces ghanaensis and related organisms.It is always used as animal feed antibiotic additives.In this thesis,the growth characteristics and inoculation standard for Streptomyces ghanaensis,fermentation conditions,feeding process,and the optimization of fermentation medium were studied.The seed culture conditions,growth characteristics and inoculation standards of Streptomyces ghanaensis were studied in shake flask.The results showed that the cultivation of single colony on the plate for 8 days were the best inoculation standard of the slant strains.The optimized culture conditions of liquid seed were established in shake flask with baffles,culture temperature at 34 C,initial pH of 7.0.The inoculation standards of liquid seed consisted of cell concentration(35%-41%),pH(6.9?7.0 after the second drop),reduced sugar(28.8?30.0 g/L),amino nitrogen(1.05-2.57 mg/L after the second drop)and inoculum age(44?48 h).Using optimal seed culture technology and inoculation standard,the final relative fermentation titer of flavomycin was increased by 35.28%,and the divergence between different batches was less than 7%.Response surface methodology(RSM)was used to optimize the fermentation conditions,including fermentation temperature,initial pH,seed age,liquid medium volumn,inoculum dose,rotate speed.The results showed that the optimum conditions were as followings:temperature 36?,pH7.2,seed age 45h,liquid medium volumn 50mL,inoculum dose 8%,rotate speed 240 r/min.The titer of flavomycin was increased by 63.42%.The feeding process for flavomycin fermentation was studied.The results showed that supplying corn steep liquor and oil after reducing the oil of the fermentation medium,the final flavomycin relative titer was increased by 51.92%,amplicating on the 5L fermentorResponse surface methodology(RSM)was used to optimize the fermentation medium,including carbon sources,nitrogen sources,inorganic salt and emulsifier.Three significant factors(soybean cake meal,corn flour and CaCO3)were ensured,and the optimum medium was determined.The relaive titer of flavomycin was increased by 60.53%.