Abstract: The effective carbon sources were screened by the growth curve of Streptomyces ghanaensis and the transcription analyses of moenomycin biosynthetic genes. The results indicated that residual sugar concentration in the fermentation medium reached the lowest level at 84 h. At the moment， the addition of glucose and sucrose with high concentrations could obviously inhibit the moenomycin biosynthesis. The RT\|PCR results showed that the transcription level of the moenomycin biosynthetic genes were 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.

Key words: moenomycin, Streptomyces ghanaensis, carbon source, sucrose, transcriptional analysis