Biosynthesis Of Mildiomaycin Derivative And Its Analysis Identification

Mildiomycin, a new nucleoside antibiotic, showed remarkable biological activity against powdery mildews of many plants with low toxicity. Two new nucleoside antibiotics (named as HIL and FIL) were isolated from the fermentation broth of Streptoverticillium rimofaciens ZJU 5119 by adding cytosine anologs to the culture medium. Further investigations were carried out about the fermentation conditions, separation processes and bioactivity, including structure indentification and toxicity test.1. An RP-HPLC method for the analysis of mildiomycin analogs in fermentation broth was developed. With this method, mildiomycin and its analogs could be separated very well and kept in good linear relationship.2. The fermentation conditions of HIL and FIL were optimized. The effects of precursor adding time, medium volume, compounds with N, N structure, precursor concentration and culture time on mildiomaycin analogs were studied in the shaking flasks. The strain grew better and the productivity became higher after the optimization. Based on the results in shaking flasks's fermentation, the fermentation of mildiomycin analogs was scaled up in a 10 L fermentor, with the same productivity as in shaking flasks.3. A separation process for HIL and FIL was developed, based on the separation method of mildiomaycin. The molecular structures of HIL and FIL were identified by ESI and ¹H-NMR spectrum. The results indicated that compounds HIL and FIL are analogs of mildiomycin with the difference of substituent on cytosine domain, in HIL it is H and in FIL it is F instead of methyl hydroxyl group in MIL.4. Antifungal activity against plant pathogenic fungi indicated that the value of EC₉₀ for HIL and FIL was 54.47mg/L and 52.89 mg/L separately; much more effective than mildiomaycin (EC90 153.22 mg/L) and triazolone (which prevention effect was 68.89% under the concentration of 100 mg/L). A further security test showed that compounds HIL and FIL were all safe pesticides with low toxicity, meet the national security standard.