The Preliminary Study Of Aspergillus Fumigatus TMS-26 Fed-batch Fermentation

Among plant secondary metabolites,taxol is a highly efficient anti-cancer drug and successfully used for application against a wide range of tumors.But it is still mainly extracted from the bark of yews which grow very slowly and are a rare and endangered species at the present time.There is an urgent need to find new production methods.Several endophytic fungi that produce taxol have been isolated from Taxus plants which shows a new resource for the production of taxol by endofungus fermentation.In our laboratory Rongfeng Fang isolated a taxol-producing fungi Aspergillus fumigatus TMS-26 from Taxus media in 2014.In this paper,based on shake flask fermentation conditions,we gradually established a 5 L fermentation conditions,and to study its supplemented with glycerol and precursors in order to improve the fermentation yield of taxol.The results are as follows:1.Based on shake flask fermentation,we performed shake flask fed-batch fermentation research determined by single factor experiment effect of glycerol,nitrogen source,precursor and CuSO4,and at the same time to explore the different temperature control modes on the effects of paclitaxel fermentation.We found that in the eighth day of fermentation supplemented with glycerol,on the tenth day of additional nitrogen,in the tenth day of additional precursor,in the ninth day supplemented with CuSO4,temperature control for the 0~9 days to maintain 28 ℃,next 9~13 days every other day increased by 1℃.In this conditions,the highest yield of taxol is obtained.2.Based on the shaking flask fermentation experiment,the amplification of the5 L tank was studied in the determination of the batch fermentation condition,the fermentation conditions of 5 L were determined,and the curve of the fermentation process of 5 L was drawn.The fermentation conditions of the final 5 L tank is pH 6,0~9 days temperature control at 28℃,9~13 days every other day increased by 1℃,until the temperature is 32℃,aeration rate 1~4 L/min,agitation speed of 80r/min~300 r/min,dissolved oxygen control in about 20%~40%.In this condition the highest yield(713.06 μg/L)of taxol is obtained in thirteenth day.3.Based on the shaking flask fermentation and 5 L tank batch fermentation,the5 L tank fed-batch fermentation was studied.And we focus on the effect of the method of adding glycerol and precursor on the production of taxol in 5 L tank.In glycerol feeding,the intermittent one time feeding,constant feeding and pH-stat feeding on fermentation to produce taxol,we found pH-stat feeding has the greatest effect on fermentation to produce taxol.In precursor feeding,the intermittent one time feeding,intermittent second feeding and constant feeding on fermentation to produce taxol,we found that the constant feeding on fermentation production of taxol by the greatest impact.Under this condition,the yield of taxol can reach 746.1 μg/L.