Study On Breeding And Optimization Of Fermentation Technics Of Streptomyces Gilvosporeus HCCB13086

Natamycin is a type of six-member ring polyene macrolide antibiotic with wide spectrum anti-fungi activity,high efficiency and safety to mammalian cellsmamm,and are always used in food and medicine domain to inhibit fungi growth.Natamycin is highly welcomed in market but its fermentation titer is low,which limits its prospect.Systematic research was made in this study on the fermentation optimization and strain breeding of Streptomyces gilvosporeus HCCB13086 producing natamycin.The main achievements were the following:1.A quick method of natamycin detection in 96 well plates was estabalished,which is suitable for preliminary screen of large scale of samples and easy to use.2.The influence of adding different amino acids into solid slant medium was observed which brought us to the best HCCB13086 medium formula.3.The influence of different factors on flask fermentation results was investigated.The best pH was determined to be 6.5-7.5,the best volume 25ml/250mlL,the best subcultivation time 24-27 hours,the best temperature 25?,the best subcultivation volume 10%.Response surface research was carried out to optimize the formula,and the best result was?g/L?:glucose 32,soybean oil 28.9,arginine 4.2,starch 50,yeast powder 30,MgSO₄·7H₂O 1,KH₂PO₄ 0.5,The production was 8.05g/L,which was increased by 53%to the original formula.4.The mutation strain was dealt with NTG associated with ultraviolet mutation followed by streptomycin resistance screening.The production was 7.43g/L,increased by 35%to the original strain.5.Heme synthesis gene hemA1,hemB,hemC,hemE,hemH and Vitreoscilla Hemoglobin gene?vgb?and positive control gene SGNRII were heterologous expressed in Streptomyces gilvosporeus HCCB13086 by conjugative transfer,and we found that the heterologous expression of hemA1 could increase the natamycin production by 64%in low dissolved oxygen environment.