The Research Of Moenomycin Fermentation Technology Of Streptomyces Ghanaensis

Moenomycin A(MmA)is the founding member of the moenomycin family of antibiotics,produced by Streptomyces ghanaensis and related organisms.It is always used as animal feed antibiotic additives as animal growth promoters.In this thesis,the growth curve of S.ghanaensis,the transcription analyses of moenomycin biosynthetic relative genes,the effect of carbon source and nitrogen source metabolic regulation during the moenomycin biosynthesis were studied.Primers were designed according to the data obtained from the S.ghanaensis ATCC14672 and S.coelicolor A(3)2 genome sequences,seeking and cloning the moenomycin biosynthetic relative genes: moeE5,moeO5,moeX5,moeGT2,yngB,glmU,ugdH,glnA,gln ? based on moenomycin biosynthetic pathway.By analysising the transcription of moenomycin biosynthetic relative genes,finding the trend of gene transcription and moenomycin production rate are related.The residual sugar concentration in the fermentation medium reached the lowest levelat 84 h bying the growth curve of S.ghanaensis,so determined the 84 h as supplementary time.In 84 h,the addition of sucrose could be a useful for improvement of moenomycin biosynthesis.The RT-PCR results showed that the transcription level of the moenomycin biosynthetic genes was promoted by the addition of sucrose.The final titer of moenomycin was improved by 14.3% with the addition of 0.5% sucrose.The addition of sucrose could promote the synthesis of related substrates involved in moenomycin biosynthesis.As a result,the moenomycin yield was improved.Researching the nitrogen source metabolic regulation of S.ghanaensis SG-1,the results reported here suggest that,the final titer of moenomycin was improved by 10.3% with the addition of corn starch powder in 60 h.The addition of corn starch powder could promote the synthesis of glutamine involved in moenomycin biosynthesis.The final titer of moenomycin was improved by 19.7% with the addition of corn starch powder in 60 h and sucrose in 84 h.By analysising the transcription of moenomycin biosynthetic relative genes,finding the addition of corn starch powder and sucrose could promote the synthesis of precursor involved in moenomycin biosynthesis,also could promote the transcription of moe cluster?and the production of moenomycin.